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Multi Threading

Java is a multi-threaded programming language which means we can develop multi-threaded program using Java. A multi-threaded program contains two or more parts that can run concurrently and each part can handle a different task at the same time making optimal use of the available resources specially when your computer has multiple CPUs.

By definition, multitasking is when multiple processes share common processing resources such as a CPU. Multi-threading extends the idea of multitasking into applications where you can subdivide specific operations within a single application into individual threads. Each of the threads can run in parallel. The OS divides processing time not only among different applications, but also among each thread within an application.

Multi-threading enables you to write in a way where multiple activities can proceed concurrently in the same program.

Life Cycle of a Thread

A thread goes through various stages in its life cycle. For example, a thread is born, started, runs, and then dies. The following diagram shows the complete life cycle of a thread.

Following are the stages of the life cycle

New − A new thread begins its life cycle in the new state. It remains in this state until the program starts the thread. It is also referred to as a born thread.

Runnable − After a newly born thread is started, the thread becomes runnable. A thread in this state is considered to be executing its task.

Waiting − Sometimes, a thread transitions to the waiting state while the thread waits for another thread to perform a task. A thread transitions back to the runnable state only when another thread signals the waiting thread to continue executing.

Timed Waiting − A runnable thread can enter the timed waiting state for a specified interval of time. A thread in this state transitions back to the runnable state when that time interval expires or when the event it is waiting for occurs.

Terminated (Dead) − A runnable thread enters the terminated state when it completes its task or otherwise terminates.

Thread Priorities

Every Java thread has a priority that helps the operating system determine the order in which threads are scheduled.

Java thread priorities are in the range between MIN_PRIORITY (a constant of 1) and MAX_PRIORITY (a constant of 10). By default, every thread is given priority NORM_PRIORITY (a constant of 5).

Threads with higher priority are more important to a program and should be allocated processor time before lower-priority threads. However, thread priorities cannot guarantee the order in which threads execute and are very much platform dependent.

Create a Thread by Implementing a Runnable Interface

If your class is intended to be executed as a thread then you can achieve this by implementing a Runnable interface. You will need to follow three basic steps −

Step 1

As a first step, you need to implement a run() method provided by a Runnable interface. This method provides an entry point for the thread and you will put your complete business logic inside this method. Following is a simple syntax of the run() method −

public void run( )

Step 2

As a second step, you will instantiate a Thread object using the following constructor −

Thread(Runnable threadObj, String threadName);

Where, threadObj is an instance of a class that implements the Runnable interface and threadName is the name given to the new thread.

Step 3

Once a Thread object is created, you can start it by calling start() method, which executes a call to run( ) method. Following is a simple syntax of start() method

#Multi Threading #explain Multi Threading #what is Multi Threading #advantages of Multi Threading #benifits of Multi Threading #features of Multi Threading

Proxy Server

Proxy Server Definition

A proxy server is a system or router that provides a gateway between users and the internet. Therefore, it helps prevent cyber attackers from entering a private network. It is a server, referred to as an “intermediary” because it goes between end-users and the web pages they visit online.

When a computer connects to the internet, it uses an IP address. This is similar to your home’s street address, telling incoming data where to go and marking outgoing data with a return address for other devices to authenticate. A proxy server is essentially a computer on the internet that has an IP address of its own.

Proxy Servers and Network Security

Proxies provide a valuable layer of security for your computer. They can be set up as web filters or firewalls, protecting your computer from internet threats like malware.

This extra security is also valuable when coupled with a secure web gateway or other email security products. This way, you can filter traffic according to its level of safety or how much traffic your network—or individual computers—can handle.

How to use a proxy? Some people use proxies for personal purposes, such as hiding their location while watching movies online, for example. For a company, however, they can be used to accomplish several key tasks such as:

1. Improve security

2. Secure employees’ internet activity from people trying to snoop on them

3. Balance internet traffic to prevent crashes

4. Control the websites employees and staff access in the office

5. Save bandwidth by caching files or compressing incoming traffic

How a Proxy Works

Because a proxy server has its own IP address, it acts as a go-between for a computer and the internet. Your computer knows this address, and when you send a request on the internet, it is routed to the proxy, which then gets the response from the web server and forwards the data from the page to your computer’s browser, like Chrome, Safari, Firefox, or Microsoft Edge

How to Get a Proxy

There are hardware and software versions. Hardware connections sit between your network and the internet, where they get, send, and forward data from the web. Software proxies are typically hosted by a provider or reside in the cloud. You download and install an application on your computer that facilitates interaction with the proxy.

Often, a software proxy can be obtained for a monthly fee. Sometimes, they are free. The free versions tend to offer users fewer addresses and may only cover a few devices, while the paid proxies can meet the demands of a business with many devices.

How Is the Server Set Up?

To get started with a proxy server, you have to configure it in your computer, device, or network. Each operating system has its own setup procedures, so check the steps required for your computer or network.

In most cases, however, setup means using an automatic configuration script. If you want to do it manually, there will be options to enter the IP address and the appropriate port.

How Does the Proxy Protect Computer Privacy and Data?

A proxy server performs the function of a firewall and filter. The end-user or a network administrator can choose a proxy designed to protect data and privacy. This examines the data going in and out of your computer or network. It then applies rules to prevent you from having to expose your digital address to the world. Only the proxy’s IP address is seen by hackers or other bad actors. Without your personal IP address, people on the internet do not have direct access to your personal data, schedules, apps, or files.

With it in place, web requests go to the proxy, which then reaches out and gets what you want from the internet. If the server has encryption capabilities, passwords and other personal data get an extra tier of protection.

Benefits of a Proxy Server

Proxies come with several benefits that can give your business an advantage:

1. Enhanced security: Can act like a firewall between your systems and the internet. Without them, hackers have easy access to your IP address, which they can use to infiltrate your computer or network.

2. Private browsing, watching, listening, and shopping: Use different proxies to help you avoid getting inundated with unwanted ads or the collection of IP-specific data.

3. Access to location-specific content: You can designate a proxy server with an address associated with another country. You can, in effect, make it look like you are in that country and gain full access to all the content computers in that country are allowed to interact with.

4. Prevent employees from browsing inappropriate or distracting sites: You can use it to block access to websites that run contrary to your organization’s principles. Also, you can block sites that typically end up distracting employees from important tasks. Some organizations block social media sites like Facebook and others to remove time-wasting temptations.

Types of Proxy Servers

While all proxy servers give users an alternate address with which to use the internet, there are several different kinds—each with its own features.

Forward Proxy

A forward proxy sits in front of clients and is used to get data to groups of users within an internal network. When a request is sent, the proxy server examines it to decide whether it should proceed with making a connection.

A forward proxy is best suited for internal networks that need a single point of entry. It provides IP address security for those in the network and allows for straightforward administrative control. However, a forward proxy may limit an organization’s ability to cater to the needs of individual end-users.

Transparent Proxy

A transparent proxy can give users an experience identical to what they would have if they were using their home computer. In that way, it is “transparent.” They can also be “forced” on users, meaning they are connected without knowing it.

Transparent proxies are well-suited for companies that want to make use of a proxy without making employees aware they are using one. It carries the advantage of providing a seamless user experience. On the other hand, transparent proxies are more susceptible to certain security threats, such as SYN-flood denial-of-service attacks.

Anonymous Proxy

An anonymous proxy focuses on making internet activity untraceable. It works by accessing the internet on behalf of the user while hiding their identity and computer information.

A transparent proxy is best suited for users who want to have full anonymity while accessing the internet. While transparent proxies provide some of the best identity protection possible, they are not without drawbacks. Many view the use of transparent proxies as underhanded, and users sometimes face pushback or discrimination as a result.

High Anonymity Proxy

A high anonymity proxy is an anonymous proxy that takes anonymity one step further. It works by erasing your information before the proxy attempts to connect to the target site.

The server is best suited for users for whom anonymity is an absolute necessity, such as employees who do not want their activity traced back to the organization. On the downside, some of them, particularly the free ones, are decoys set up to trap users in order to access their personal information or data.

Distorting Proxy

A distorting proxy identifies itself as a proxy to a website but hides its own identity. It does this by changing its IP address to an incorrect one.

Distorting proxies are a good choice for people who want to hide their location while accessing the internet. This type of proxy can make it look like you are browsing from a specific country and give you the advantage of hiding not just your identity but that of the proxy, too. This means even if you are associated with the proxy, your identity is still secure. However, some websites automatically block distorting proxies, which could keep an end-user from accessing sites they need.

Data Center Proxy

Data center proxies are not affiliated with an internet service provider (ISP) but are provided by another corporation through a data center. The proxy server exists in a physical data center, and the user’s requests are routed through that server.

Data center proxies are a good choice for people who need quick response times and an inexpensive solution. They are therefore a good choice for people who need to gather intelligence on a person or organization very quickly. They carry the benefit of giving users the power to swiftly and inexpensively harvest data. On the other hand, they do not offer the highest level of anonymity, which may put users’ information or identity at risk.

Residential Proxy

A residential proxy gives you an IP address that belongs to a specific, physical device. All requests are then channeled through that device.

Residential proxies are well-suited for users who need to verify the ads that go on their website, so you can block cookies, suspicious or unwanted ads from competitors or bad actors. Residential proxies are more trustworthy than other proxy options. However, they often cost more money to use, so users should carefully analyze whether the benefits are worth the extra investment.

Public Proxy

A public proxy is accessible by anyone free of charge. It works by giving users access to its IP address, hiding their identity as they visit sites.

Public proxies are best suited for users for whom cost is a major concern and security and speed are not. Although they are free and easily accessible, they are often slow because they get bogged down with free users. When you use a public proxy, you also run an increased risk of having your information accessed by others on the internet.

Shared Proxy

Shared proxies are used by more than one user at once. They give you access to an IP address that may be shared by other people, and then you can surf the internet while appearing to browse from a location of your choice.

Shared proxies are a solid option for people who do not have a lot of money to spend and do not necessarily need a fast connection. The main advantage of a shared proxy is its low cost. Because they are shared by others, you may get blamed for someone else’s bad decisions, which could get you banned from a site.

SSL Proxy

A secure sockets layer (SSL) proxy provides decryption between the client and the server. As the data is encrypted in both directions, the proxy hides its existence from both the client and the server.

These proxies are best suited for organizations that need enhanced protection against threats that the SSL protocol reveals and stops. Because Google prefers servers that use SSL, an SSL proxy, when used in connection with a website, may help its search engine ranking. On the downside, content encrypted on an SSL proxy cannot be cached, so when visiting websites multiple times, you may experience slower performance than you would otherwise.

Rotating Proxy

A rotating proxy assigns a different IP address to each user that connects to it. As users connect, they are given an address that is unique from the device that connected before it.

Rotating proxies are ideal for users who need to do a lot of high-volume, continuous web scraping. They allow you to return to the same website again and again anonymously. However, you have to be careful when choosing rotating proxy services. Some of them contain public or shared proxies that could expose your data.

Reverse Proxy

Unlike a forward proxy, which sits in front of clients, a reverse proxy is positioned in front of web servers and forwards requests from a browser to the web servers. It works by intercepting requests from the user at the network edge of the web server. It then sends the requests to and receives replies from the origin server.

Reverse proxies are a strong option for popular websites that need to balance the load of many incoming requests. They can help an organization reduce bandwidth load because they act like another web server managing incoming requests. The downside is reverse proxies can potentially expose the HTTP server architecture if an attacker is able to penetrate it. This means network administrators may have to beef up or reposition their firewall if they are using a reverse proxy.

Proxy Server vs. VPN

On the surface, proxy servers and virtual private networks (VPNs) may seem interchangeable because they both route requests and responses through an external server. Both also allow you to access websites that would otherwise block the country you’re physically located in. However, VPNs provide better protection against hackers because they encrypt all traffic.

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Django

Django:

Django—pronounced “Jango,” named after the famous jazz guitarist Django Reinhardt—is a free, open source framework that was first publicly released in 2005. Django facilitates “rapid development and clean, pragmatic design.” The Django web framework, deployed on a web server, can help developers quickly produce a web frontend that’s feature-rich, secure and scalable.

Starting with the Django web framework is more efficient way to build a web app than starting from scratch, which requires building the backend, APIs, javascript and sitemaps. With the Django web framework, web developers can focus on creating a unique application and benefit from greater flexibility than using a web development tool.

Getting to know the Django web framework

Do you need more information to discover what is Django and how it's used? Do you want some hands-on experience working with a web app created using the Django web framework? IBM offers a step-by-step tutorial for using IBM Cloud services to track activity and monitor the health of a Python-based Kubernetes application written using the Django web framework and running on the IBM Cloud.

With all the Python web frameworks to choose from, why pick Django web framework? It might not be the easiest to use and it’s certainly not the newest. Nevertheless, the Django web framework might be the right fit when you’re building a web app that’s involves cross-site scripting and is expected to handle a large number of users or a complex set of features, such as API connectivity or user authentication. Based on the number of projects on GitHub, it's also very popular.

Anyone proficient in the Python programming language and its syntax should be able to start a project using Django web framework to build a web app. (Note: While most of Django core is Python, the admin and gis contrib apps contain JavaScript code.) However, intermediate to advanced Django developers can better capitalize on Django models, which are more sophisticated features.

Packaging essential features

Django include:

Forms: HTML Forms are used to collect user data for processing on the server. Django simplifies form creation, validation, and processing.

User authentication and permissions: Django includes a robust user authentication and permission system that has been built with security in mind.

Caching: Creating content dynamically is much more computationally intensive (and slow) than serving static content. Django provides flexible caching so that you can store all or part of a rendered page so that it doesn't get re-rendered except when necessary.

Administration site: The Django administration site is included by default when you create an app using the basic skeleton. It makes it trivially easy to provide an admin page for site administrators to create, edit, and view any data models in your site.

Serializing data: Django makes it easy to serialize and serve your data as XML or JSON. This can be useful when creating a web service (a website that purely serves data to be consumed by other applications or sites, and doesn't display anything itself), or when creating a website in which the client-side code handles all the rendering of data.

Django web framework has been in use for more than a decade and has been thoroughly tested and enhanced by a very active community. It even has a non-profit; the Django software foundation promotes, supports and advances the Django web framework. Django’s greatest strength is its large feature set—with more than 10,000 Django packages, the framework covers virtually anything you’ll need a web application to do. Packages include APIs, content management systems, user authentication, form validation and CAPTCHA protection.

The user base for Django web framework is supportive and dedicated, full of talented Django developers volunteering their time and expertise to develop, improve and patch the Django software foundation. Your application can benefit from this commitment by tapping into the well-designed packages available to anyone building with Django.

Benefits

Make database management more Python-like

Starting a Django project allows you to build your application’s entire data model in Python without needing to use SQL. Using an object-relational mapper (ORM), Django converts traditional database structure into Python classes to make it easier to work within a fully Python environment. Django-MySQL supports the JSON data type and related functions.

In Django, your database tables become Python classes. Web applications access and manage data through Django models. The fields of the database are simply converted into class attributes. If you’re familiar with class attribute definition in Python, you can easily design and manage a Django database.

Django Web Framework offers a shortcut to full integration with your application’s database. It provides CRUD (create, read, update, delete) functionality, HttpResponse and cross-site scripting, supplies user management capabilities, offers software administration features and more. You import the packages, connect to your database and then get back to work developing the parts of your application that make your product unique.

In a traditional data-driven website, a web application waits for HTTP requests from the web browser (or other client). When a request is received the application works out what is needed based on the URL and possibly information in POST data or GET data. Depending on what is required it may then read or write information from a database or perform other tasks required to satisfy the request. The application will then return a response to the web browser, often dynamically creating an HTML page for the browser to display by inserting the retrieved data into placeholders in an HTML template.

Django web applications typically group the code that handles each of these steps into separate files:

URLs: While it is possible to process requests from every single URL via a single function, it is much more maintainable to write a separate view function to handle each resource. A URL mapper is used to redirect HTTP requests to the appropriate view based on the request URL. The URL mapper can also match particular patterns of strings or digits that appear in a URL and pass these to a view function as data.

View: A view is a request handler function, which receives HTTP requests and returns HTTP responses. Views access the data needed to satisfy requests via models, and delegate the formatting of the response to templates.

Models: Models are Python objects that define the structure of an application's data, and provide mechanisms to manage (add, modify, delete) and query records in the database.

Templates: A template is a text file defining the structure or layout of a file (such as an HTML page), with placeholders used to represent actual content. A view can dynamically create an HTML page using an HTML template, populating it with data from a model. A template can be used to define the structure of any type of file; it doesn't have to be HTML!

Create dynamic pages with templates

Because Django is designed to be used for web app development, it needs a way to easily create dynamic HTML that displays your user’s unique data. The Django application produces that dynamic HTML with a built-in templating engine called the Django template language (DTL).

An HTML template allows Django developers to combine static elements (including design elements such as colors, logos, or text) with data (such as user names or locations) to create a new web page on the fly. With model-view-controller (MVC), if you want your application to greet a user by name when they log in, you can build a template that displays the static text (“Welcome to the site, X”) then use a dynamic placeholder to automatically display the user’s first name from your database. When the page renders, it will combine the dynamic elements with the static ones to create a seamless user experience.

Enhance security

When answering, "What is Django", we must talk about what special features Django offers for security. Web apps are frequent targets of hackers, especially applications that store user login information or financial data. Django offers features to help protect your application and your users.

One of the biggest risks for sites that accept user-entered data is that a malicious user will inject code with their data that can have a disastrous effect on your system. To protect against attacks like these, Django templates automatically escape common HTML characters in any user-entered field. For example, it will automatically convert ‘<’ to ‘<’ to make it difficult to inject malicious code into your program. Django protects from SQL injection in a similar way, reinterpreting unauthorized commands so that users can’t sneak their own code into your database.

Web developers can also count on Django APIs to automatically use cross-site request forgery (CSRF) protection to insert user-specific secret tokens into POST requests. As a result, web developers can prevent malicious users from duplicating other POST requests to masquerade as authorized users.

The protection of Django goes beyond its explicit security features: security efforts are enhanced by the extensive experience and expertise of the Django user base. If you build your entire web app from scratch, you run the risk of accidentally introducing a security vulnerability into your module. Django packages are widely used, open source and well reviewed by web developers, so you can be more confident that they’ll protect your data.

Scaling Django

One of the biggest challenges in web development is scalability. Your application must handle exactly the number of active connections that are required at any given time. If the connections exceed your estimate, your users will experience lags and downtime. Estimate too conservatively and you’ll pay for bandwidth and web servers you’re not using. You need an application that can grow as you gain more users.

Django web framework makes scaling easy. Because a Django app can manage your user sessions, you can add more instances of your application and transfer the user’s experience across the instances without losing data. Many Django project developers also use a cache manager such as Varnish to pre-load the static elements of the site for users.

You’ll need to carefully configure the cache manager to avoid accidentally caching your entire site, including the dynamic elements. A poorly configured cache could also lead to sharing data from one user to the next. You can avoid over-caching by using Django’s native (but limited) cache framework in conjunction with an external cache manager to free up performance resources while being selective on what is stored.

When answering the question, "What is Django," one answer is that it is a highly scalable web framework. Just how scalable is it? Instagram and Disqus are among the very large sites that use Django to support their huge user bases.

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Google Lens

Google Lens:

Google Lens is a set of vision-based computing capabilities that can understand what you’re looking at and use that information to copy or translate text, identify plants and animals, explore locales or menus, discover products, find visually similar images, and take other useful actions.

Search what you see

Google Lens lets you search what you see. Using a photo, your camera or almost any image, Lens helps you discover visually similar images and related content, gathering results from all over the internet.

How Google Lens works

Lens compares objects in your picture to other images, and ranks those images based on their similarity and relevance to the objects in the original picture. Lens also uses its understanding of objects in your picture to find other relevant results from the web. Lens may also use other helpful signals, such as words, language, and other metadata on the image’s host site, to determine ranking and relevance. Read More

When analyzing an image, Lens often generates several possible results and ranks the probable relevance of each result. Lens may sometimes narrow these possibilities to a single result. Let’s say that Lens is looking at a dog that it identifies as probably 95% German shepherd and 5% corgi. In this case, Lens might only show the result for a German shepherd, which Lens has judged to be most visually similar. In other cases, when Lens is confident it understands which object in the picture you’re interested in, Lens will return Search results related to the object. For example, if an image contains a specific product - like jeans or sneakers - Lens may return results providing more information about that product, or shopping results for the product. Lens may also rely on available signals, like the product’s user ratings, to return such results. In another example, if Lens recognizes a barcode or text in an image (for example, a product name or a book title), Lens may return a Google Search results page for the object.

Relevant and useful results

Lens always tries to return the most relevant and useful results. Lens’ algorithms aren’t affected by advertisements or other commercial arrangements. When Lens returns results from other Google products, including Google Search or Shopping, the results rely on the ranking algorithms of those products. To ensure Lens results are relevant, helpful, and safe, Lens identifies and filters explicit results. These results are identified using Google-wide standards such as Google SafeSearch guidelines.

Lens & location

When you agree to let Lens use your location, it uses that information to return more accurate results - for example, when identifying places and landmarks. So if you’re in Paris, Lens will know that it’s more likely you’re looking at the Eiffel Tower rather than a similar-looking structure somewhere else in the world.

1: Copy text from the real world

Google Lens's most potent power and the one I rely on most frequently is its ability to grab text from a physical document — a paper, a book, a whiteboard, or anything else with words on it — and then copy that text onto your phone's clipboard. From there, you can easily paste the text into a Google Doc, a note, an email, a Slack chat, or anywhere else imaginable.

To do that, just open up the Google Lens app, tap the document icon, and aim your phone at the document. Within about a second, you'll see Lens highlight the text.

Tap your finger onto any area of the image, and you'll be able to select the exact portion of text you want as if it were regular ol' digital text on a website.

All that's left is to hit the "Copy" command in the panel at the bottom of the screen, and every last word will be on your system clipboard and ready to paste wherever your pretty little heart desires.

2: Interact with text from an image

In addition to the live stuff, Lens can pull and process text from images — including both actual photos you've taken and screenshots you've captured.

That latter part opens up some pretty interesting possibilities. Say, for instance, you've just gotten an email with a tracking number in it, but the tracking number is some funky type of text that annoyingly can't be copied. (This seems to happen to me way too often.) Or maybe you're looking at a web page or presentation where the text for some reason isn't selectable.

Well, grab a screenshot — by pressing your phone's power and volume-down buttons together — then make your way over to the Google Lens app. Tap the square-shaped photo icon in the app's upper-right corner, select the screenshot you just captured, and then select the text you want.

3: Search for text from any physical document or image

After you've selected any manner of text from within the Google Lens app, swipe your finger toward the left on the row of options in that bottom-of-screen panel — the one with "Copy text," "Copy to computer," and so on. You'd never realize it from looking, but even more options are hiding to the right of those initial choices.

One of 'em is the simple but supremely useful "Search." (And sometimes, Lens will even put related results right there in that bottom-of-screen panel, without any additional searching required.) Keep that in mind as a super-easy way to get info on any text from any physical document or captured image without having to manually peck in the words on your own.

4: Create a calendar event

Anytime you see something with a date involved — a flyer, a billboard, an appointment card, or even a physical invitation to your dear Aunt Sally's weekly canasta game — save yourself the trouble of typing the info into your digital calendar and instead just open up the Google Lens app.

Aim your phone's camera at the paper and then tap on the date. Lens should give you a "Create calendar event option" at the start of its bottom-panel choices, and tapping it will beam the info right over to your preferred calendar app so you can tweak it as needed and save.

5: Save someone's contact information

If you find yourself holding a business card and thinking, "Well, blimey, I sure as heckfire don't want to type all of this into my contacts app," first, congratulate yourself on the excellent use of blimey — and then sit your beautiful person-shell back and let Lens handle the heavy lifting for you.

Open Lens, point your phone's camera at the card, and tap on the person's name. The Google Lens app should recognize the nature of the info and prompt you to add a contact.

6: Email, call, text, or navigate to a website

Got an address or number you need to get onto your phone for a specific sort of action? It could be on a business card, on a letter, or even on the front of a door. Whatever the case, just open the Google Lens app, point your phone at it, and tap the text. (Or, option B: Snap a photo of the info in question and then pull it up in the Lens app later.)

Once Lens sees it, it'll offer to do whatever's most appropriate for the sort of info involved. Then, with a single tap, you'll have the address ready to roll in a new email draft, the number ready to call or text in your dialer or messaging app, or the website pulled up and ready for your viewing in your browser — no time-wasting typing required.

7: Translate text from the real world

If, in some theoretical future where travel is again common, you find yourself staring at a sign in another language and wondering what in the world it says, remember that the Google Lens app has a built-in translation feature. To find it, open the app, aim your phone at the text, and tap the translate icon — the circle with an "A" inside of it at the far left of the bottom row.

Before you know it, Lens will replace the words on your screen with their English equivalents (or with a translation in whatever language you select, if English isn't your tasse de thé). It's almost spooky how effective it is.

8: Scan barcodes and QR codes

'Twas a time when Android code-reading apps were all the rage — and plenty of folks still have 'em hangin' around today. So long as the Google Lens app is on your phone, though, guess what? You don't need anything else. Just open up Lens, aim your camera at any barcode or QR code, and poof: Lens will offer to show you whatever that code contains, faster than you say "What does QR stand for, anyway?"

9: Use Lens from Image Search, Photos, and your phone's camera

All those tricks we just talked about can work not only from the actual Google Lens app but also from a few other potentially useful places on your phone:

· Google Image Search: Anytime you're looking at an image within images.google.com on your phone's browser, keep an eye out for the lens icon in its upper-right corner. Tapping that will activate Lens and give you any relevant info about whatever's being shown.

· Google Photos: See that third icon along the bottom when you open an image in Photos? That's Lens! Tapping it will fire up Lens and let you copy text, activate links, and get additional context about anything Lens is able to recognize.

Your camera: On Pixel phones and a handful of other devices, you can find Lens right within your regular camera app. Just open the camera and then press and hold your finger on any spot in the viewfinder to launch a Lens search for the item in view. The results will pop up right then and there, without the need for any app-switching or extra searching.

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Web Applications

Web Application :

Whether your company has a local, national or global reach, easy and quick interactions with employees and clients have become more necessary than ever in the business world. Increasingly, companies are using web applications to facilitate communication and the exchange of information. Understanding what a web application is can help you realise its importance in your everyday life. In this article, we aim to answer the question, "What is a web application?" and discuss how it works and its benefits.

What is a web application?

A website application, which is also popularly known as a web app, is a software application program that uses web-based technology to perform specific tasks. Remote web servers host web applications and store relevant information from numerous connected computers. You can use a client program to run the web applications and access or enter the required data. That is why people often refer to web apps as client-server programs.

Larry Wall developed one of the first web applications in 1987. It was a server-side Unix scripting language known as Perl and was useful for processing reports. Since then, web applications have undergone many developments, and the current ones are far more sophisticated in their features and use than the earlier simplistic ones. They are also far more indispensable for personal and business use.

How does a web application work?

A web app requires mainly three elements to function properly. This includes a web server to handle requests from the client, an application server to execute the tasks requested and a database to store the information. Here is how a web application typically works:

The user will connect to the Internet and create a request to the web server through the application's user interface.

The web server will process the request and send it to the right web app server.

The web application server will perform the required task and generate the results of the required data.

The web app server will send the information back to the web server.

The web server will send the requested information to the client's device such as a laptop, desktop or mobile phone.

The requested information will appear on the user's display.

A developer's role in a web application

When developing a web app, the developer generally codes it for functionality using a combination of server-side script languages and client-side scripting languages. For instance, they may use Java, Python, PHP and ASP for the server-side script and HTML5, CSS and JavaScript for the client-side script. The purpose of the server-side script is to allow the web application to store information on the web server and to retrieve it when necessary. The client-side script is for presenting the information to the users. After the compatible browsers execute and run the program, the user can access the information they want.

Generally, small teams can conceive and design many web apps. At the start, they will decide whether they need to create dynamic web apps that need server-side processing or static web applications that do not require server-side processing. The development phases consist of gathering information, planning and designing the application. It is also necessary to create and assemble content. The developers will then code the web app and test and review it for errors. After launching the web application, the developers will continue to monitor it for any necessary maintenance work and feature and coding updates.

Difference between website and web application

A website and a web application have the following differences:

Basic features and purpose

A website is a collection of static, interlinked and globally accessible web pages that you can view on a compatible browser. It provides information to the viewer using text, images and videos. A web app, in comparison, is a software program with interactive content and other elements for user engagement. The user interaction determines the value or usefulness of a web application. Increasingly, it is common to see hybrid websites that combine static and interactive elements to provide a better user experience.

Compilation

It is not strictly necessary to precompile a website before you deploy it. Additionally, if you make site changes, you do not need full recompilation and deployment. It will be enough to update the HTML code. For a web application, however, precompilation is crucial for efficient deployment. The advantages will be a faster initial response time, source code protection and the ability to identify and catch errors early. Every time you make a change, recompilation and deployment are essential for the entire application.

Integration

It is optional for a website to integrate with a third party, and the process is relatively simple. For a web app, its complex functionality makes integration with third-party software programs and online tools trickier. However, third-party integration is essential for web applications for data collection, storage and processing.

User interaction

You can instantly access and view a website on a web browser. The most commonly used web browsers are Brave, Qwant, Mozilla Firefox and Safari. However, you can only see or read the website content on a browser. You cannot interact with it. A web app requires you to download and instal it on your mobile device. You can then access, interact with and manipulate its data in a personalised manner.

User authentication

A website does not require user authentication from its visitors. It may prompt them to sign up for updates or its newsletters, though. A web application will generally require user authentication before allowing access to its numerous options.

New updates

If you update your website, the updates will become immediately visible to your visitors. To upgrade a web application, you will have to visit its website or an online app outlet and download the new version on your mobile device or computer. You will then need to instal it on the device before you can use the latest features.

Benefits of web applications

Web applications have many benefits, including the following:

They are easy to instal and use on different computers and mobile devices.

They only need a compatible browser for their operation and are not dependent on any particular operating system or device.

As they can run on multiple platforms, developers do not have to build separate client-side programs for different operating systems and computers.

Since a remote web server stores the web applications, there is no need to host them locally, and you do not have to worry about the space limitations on your hard drive.

Web applications are stored on a remote web server, which reduces the need for technical support.

It is easy to make changes to web apps and keep them updated since all updates are applied centrally on the web server.

As the same web application version is available to all users, so it eliminates any compatibility issues.

If you get a custom web app for your business, you can customise and scale it and add more functionality per your business needs.

They help reduce software piracy in subscription-based web applications.

For business users, web apps offer better work management and improved work efficiency. You can use them to integrate data from multiple sources, share data spreadsheets with your team members and collaborate on projects and reports.

Web applications offer a higher level of data security, as the data is stored on remote dedicated web servers. Experienced server administrators monitor these servers for any potential breaches and take action to prevent them.

They use cloud data storage, meaning that you will not lose your data in the event that your computer or mobile device gets damaged.

Different web apps can be interoperable with each other, allowing for better web integration and adaption of emerging Internet technologies.

Example of a web application:

An email program like ProtonMail is an example of a web application. Other examples of web apps include an instant messaging app like WeChat, a social media platform like WhatsApp, a retail site like Flipkart and a photo-sharing application like Flickr. Other web apps that you might have used are Zoom and Microsoft 365. Web applications can include everything from shopping carts and spreadsheets to online banking. They have become practically indispensable across different industries for almost anything you might want to undertake.

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Computer Crime

Computer crime is an act that describes a large category of offenses, which is also known as hi-tech crime, e-crime, cybercrime, or electronic crime. It is performed by a computer user who has great knowledge about hacking. The hacker tries to gain unauthorized access to any particular account, personal information or steals a company's or individual's private information. In some cases, hackers can corrupt the computer or data files that can be very harmful to you.

On the basis of the person, situation, and individual frame of reference, the term computer crime has different meanings. For example, there are different communities like network administrators, private security, law enforcement, or prosecutors, but the investigation of computer crime does not need these communities. However, conventional or physical borders do not restrict computer crime as it is by its very nature.

The first definitional categories for computer crime are presented by Donn Parke, who is generally cited as the author. A higher-level definition to the term computer abuse was described by him, computer crime can be any event involving an planned act where a unauthorize person or offender wants to gain related to computers, but a victim suffered or could have suffered a loss.

Expanding on Parker's definitions Robert Taylor and company describe four major categories of computer crime:

HTML Tutorial

The computer as a target: Computers can be the target of an illegal activity, which means the attacker has to main objective to deny the owners or legal users of the system to their data or computer. Unleashing a virus through email is one of the most common crimes at the time of targeting computers. An example of this category (computer as a target) is a Denial-of-Service attack or a virus. A virus is referred to destroy your system's data or even a computer system, which is a computer program

The computer as an instrument of the crime: In this category, a computer is used to accomplish complex financial schemes to defraud or use to gain some information or data, which data is further used for any illegal activity. For case, a computer system can be used by a hacker to steal personal information, which can be used for the criminal objective.

The computer as incidental to a crime: The computer may be incidental to a crime that means it can only facilitate the crime but may not the primary instrument of it. For example, the trading of child pornography and money laundering.

Crimes associated with the prevalence of computers: This category comprises of the actions such as software piracy, intellectual property theft, and other crimes against the computer industry.

Examples of computer crimes

In modern times, there are various kinds of computer crime available, which are discussed below:

Child pornography: Child pornography is an example of computer crimes, which is a form of child sexual exploitation.

Cracking: Another example of computer crime is cracking, in which the cracker decodes or breaks the codes that are designed to protect data. A cracker is an individual who uses a script or program to decipher codes or breakdown security systems for illegal activities. The program or script, which is used to break the security, is known as crack.

Cyber terrorism: In this category, the attacks come, like blackmailing, hacking, threats towards a person or business to gain unauthorized access to perform illegal activities.

Cybersquatting: Cybersquatting is a term, which is also referred to as domain squatting and typo squatting that is used to set up a domain of another person or company and hold it for resale at a premium price.

Cyberbully or Cyberstalking: Cyberstalking is a kind of attack in which anyone harasses or stalks other persons online by posting inappropriate or unwanted things about them.

Creating Malware: Malware is malicious software that is installed on your computer without your consent as it uses deceptive and unethical tactics. It is designed to watch browsing habits, delete software, or even open someone's computer to attack. For case, sometimes you mistakenly run software on your computer when you are visiting a website and get an unrequested download.

Denial of Service attack: A DoS attack, which stands for denial of service attack, is a kind of computer crime in which an attacker sends an abnormally high number of requests to the victim that is led to the network slow down or fail. These requests cannot be served as normal requests.

Doxing: It is another type of attack when someone shares another person's personal information with anyone without their consent. The personal information may be in the form of someone's full name, address, history, password, and other identifying information.

Espionage: Espionage is the act of spying on a person or business to obtain secret or confidential information. A person who performs these kinds of activities is known as a spy or espionage agent. Espionage agents can work in company or independent operations to uncover agencies or other secret information.

Fraud: Fraud is the use of computers, internet services, or devices to manipulating data or defraud people or organizations; for example, to participate in credit card fraud or to transfer money to an account, changing banking records. Examples of illegal computer activities include: social engineering, DDoS, viruses, and phishing attacks are used to gain unauthorized access to another fund.

Harvesting: A harvester is a software, also known as a web harvester, that is designed to gather account or account-related information of others, or it is also used to parse large amounts of data. For instance, large numbers of web pages may be processed by a web harvester to take out names, phone numbers, email addresses, account names from the website.

Human trafficking: It is one of the serious crimes, which is an act of participating in buying or selling other humans. Basically, it graves a violation of human rights. There are thousands of men, women, and children who become a victim of traffickers. Approximately all countries in the world become a victim of attackers.

Identity theft: Identity theft is an act to be a person you are not that one. In this category, attackers try to gain information illegally about someone else. Attackers or thieves can try to information such as phone number, credit card numbers, full name, maiden name, social security number, passwords, etc.

Illegal sales: It is an act of purchasing or selling illicit goods online, such as psychotropic substances, drugs, guns, and more.

Intellectual property theft: It is a category of property where a human creates something by using their own mind. In this case, if anyone steals practical or conceptual information that is created by other persons or organizations, it comes under intellectual property theft, which is known as a crime. Trade secrets, copyrights, trademarks, and patents are well-known types of intellectual property.

Phishing or vishing: It is a term that is used to deceive individuals or groups to obtain secret information about that person. For that, they create web pages designed to gather personal information like a credit card, online bank, password, or other private information. They also do so with the help of sending emails.

Salami slicing: Generally, it can be defined as stealing small amounts of money from each transaction that builds into a large sum of illegally gained money.

Scam: A scam is a term that is used to trick people into believing something, which is not actually true. For example, people start a fraud scheme or business through which they gain money from an unsuspecting person. Online scams have increased because the world is more connected to the network. And, it depends on you to keep careful yourself from these kinds of online scams

Slander: A slander is an act of posting libel against another organization or person.

Software piracy: Generally, it describes illegally copying, distributing, or using software without ownership or legal rights. Today, most of the software may have installed on one computer to use as it is purchased as a single-user license. If you share that software with anyone or copy it on multiple computer devices without purchasing multiple licenses, it is illegal and comes under software piracy.

Spamming: Spam is an e-mail distributed process that is used to promote a specific product or a scam to obtain other people's money by sending unsolicited e-mail to thousands and sometimes millions of people without their consent. It describes junk e-mail on the Internet that is also known as UCE (unsolicited commercial e-mail), mass e-mail marketing, and bulk e-mail.

Spoofing: Generally, the term spoof describes hacking or deception that means to deceive a system by imitating another person, computer, hardware device. You do that bypassing security measures. IP spoofing is one of the well-known spoofing's.

Typosquatting: Cybersquatting is a term used to describe a domain that is a misspelling of another domain. Generally, it is also known as domain squatting and typo squatting that means a company or individual knowingly buys a domain and holds it resale at a premium price.

Unauthorized access: When someone tries to access a system, server, program, and service by using an illegal method or someone else's account information. Basically, unauthorized access means accessing a system on which you have no permission to access. For the case, you have a Gmail account, and someone kept guessing a password or username for your account and accessed this account, which is considered unauthorized access.

Wiretapping: Wiretapping is the surreptitious electronic monitoring device that is used to connect a device to a phone line to listen to conversations.

Protect Yourself against Computer Crimes

Due to a computer or cybercrime, losing account information, computer, or other personal information can be very harmful; because this information can be used by an unauthorized person for any illegal activity. Especially, there are more chances to become victims of these crimes when you are relay more and more on these networks to conduct business. However, there are different ways that can help you out to protect you from these crimes.

The online use of computers is very much involved in fraud or computer crimes. You must be careful at the time of sharing your important personal information over the internet. This information can be in terms of your social security numbers, account id, password, credit card number, etc.

Also, use a difficult password to take basic precautions for keeping your data private and change the password frequently that would be made hacking difficult. Make sure you are not doing financial transactions over unprotected networks or on public computers. A good anti-virus program also helps to prevent these crimes; so, you should install anti-virus on your system and update it regularly. Furthermore, there are various websites that can have viruses, spyware, or other malware; therefore, be careful when you are downloading software from these kinds of websites.

There are some important key points that can help you protect against computer crimes:

Use strong passwords: Always use a strong, unique password and change your password frequently. Also, the repeated password is not beneficial; so, do not keep the same passwords on different sites. And you should always try to password with the combination of at least 10 -14 letters that have symbols, special characters, and numbers, which means create a complex password. A complex password cannot be hacked easily like "123456" or "another simple password."

Keep your software updated: Especially, it is most important with your internet security software; because attackers always try to gain access to your system by using flaws or known exploits. Therefore, you should keep your software up to date, which helps to patch those exploits and flaws, which led to a decrease in the chances of becoming a victim of cybercrime.

Be careful about using public Wi-Fi: It is very easy for hackers to connect with public Wi-Fi. That means they can see your history what you're doing on the internet, such as watching a movie, including they can see your account information, password, or other personal sensitive information you are logging on the device. To protect yourself against crime, do not enter your secret information while using public Wi-Fi, and when you are on public Wi-Fi, use apps that need a password to access.

Manage your social media settings: Make sure your private and personal information is locked. As you mostly share your pictures or other data on social media sites publicly, which can be hacked by social engineering cybercriminals. So, it would be better for you to less share your personal information on social media.

Some other points keep in your mind

Be aware because identity theft can happen anywhere

Keep an eye on the children

Take measures to help protect yourself against identity theft

Strengthen your home network

Use a full-service internet security suite

You should go offline when you do not need an internet connection

Consider sharing less online

Block spyware attacks

Have A Firewall

Any computer network should be protected by a firewall. A firewall is a virtual barrier that disallows information from making its way into the network without authorization. The firewall will block out any data that has not been intentionally permitted by the network administrator.

Anti-Virus Software

The spread of computer viruses can be responsible for major losses of data and sometimes money or machinery. There are a number of anti-virus software options that will help prevent these harmful programs from getting onto a network or a single computer.

Intrusion Detection Systems

An intrusion detection system (IDS) is a good secondary line of defense in addition to a firewall. An IDS can help indicate when an internal attack is taking place or when a hacker has bypassed a firewall and obtained access to the system, according to Interpol's website.

This system identifies statistical deviations and points out unusual behavior within the network. When activity that is inconsistent with the typical tasks performed on the network occur, the IDS flags the activity and its source, alerting the appropriate people that an intrusion may be happening. The system can also be programmed to detect when certain areas of the network are tampered with and can act as a sort of burglar alarm against intrusions.

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E-wallets

What is 'E-wallets'

Definition:

E-wallet is a type of electronic card which is used for transactions made online through a computer or a smartphone. Its utility is same as a credit or debit card. An E-wallet needs to be

Linked with the individual’s bank account to make payments.

Descriptions:

E-wallet is a type of pre-paid account in which a user can store his/her money for any future online transaction. An E-wallet is protected with a password. With the help of an E-wallet,

one can make payments for groceries, online purchases, and flight tickets, among others.

· E-wallet has mainly two components, software and information. The software component stores personal information and provides security and encryption of the data. The information component is a database of details provided by the user which includes their name, shipping address, payment method, amount to be paid, credit or debit card details, etc.

Read More For setting up an E-wallet account, the user needs to install the software on his/her device, and enter the relevant information required. After shopping online, the E-wallet automatically fills in the user’s information on the payment form. To activate the E-wallet, the user needs to enter his password. Once the online payment is made, the consumer is not required to fill the order form on any other website as the information gets stored in the database and is updated automatically.

crypto wallets :

Definition

Crypto wallets store your private keys, keeping your crypto safe and accessible. They also allow you to send, receive, and spend cryptocurrencies like Bitcoin and Ethereum.

Crypto wallets keep your private keys – the passwords that give you access to your cryptocurrencies – safe and accessible, allowing you to send and receive cryptocurrencies like Bitcoin and Ethereum. They come in many forms, from hardware wallets like Ledger (which looks like a USB stick) to mobile apps like Coinbase Wallet, which makes using crypto as easy as shopping with a credit card online.

Why are crypto wallets important?

Unlike a normal wallet, which can hold actual cash, crypto wallets technically don’t store your crypto. Your holdings live on the blockchain, but can only be accessed using a private key. Your keys prove your ownership of your digital money and allow you to make transactions. If you lose your private keys, you lose access to your money. That’s why it’s important to keep your hardware wallet safe, or use a trusted wallet provider like Coinbase.

How do you use a crypto wallet?

Crypto wallets range from simple-to-use apps to more complex security solutions. The main types of wallets you can choose from include:

· Paper wallets: Keys are written on a physical medium like paper and stored in a safe place. This of course makes using your crypto harder, because as digital money it can only be used on the internet.

· Hardware wallets: Keys are stored in a thumb-drive device that is kept in a safe place and only connected to a computer when you want to use your crypto. The idea is to try to balance security and convenience.

· Online wallets: Keys are stored in an app or other software – look for one that is protected by two-step encryption. This makes sending, receiving, and using your crypto as easy as using any online bank account, payment system, or brokerage.

Each type has its tradeoffs. Paper and hardware wallets are harder for malicious users to access because they are stored offline, but they are limited in function and risk being lost or destroyed. Online wallets offered by a major exchange like Coinbase are the simplest way to get started in crypto and offer a balance of security and easy access. (Because your private info is online, your protection against hackers is only as good as your wallet provider's security – so make sure you look for features like two-factor verification.)

Using an app like Coinbase Wallet or Exodus gives you easy access to your crypto holdings. You can:

· Manage all your digital assets in one secure place

· Control your own private keys

· Send and receive cryptocurrency to and from anywhere in the world

· Interact with usernames rather than long, hexadecimal “public key” addresses

· Browse dapps (decentralized finance apps)

· Shop at stores that accept cryptocurrency

What’s the difference between the Coinbase app and Coinbase Wallet?

· The main Coinbase app (or Coinbase.com) allows you to buy and sell crypto or exchange it for fiat currency and transfer it to a bank account. If you just want to invest in Bitcoin or another digital currency it’s all you need. The Coinbase app will securely manage the rights to your private keys.

· Coinbase Wallet is a separate app that allows you to store your private keys and to send, receive, and spend digital money; browse and use DeFi applications, and more. You don’t need a Coinbase account to use Coinbase Wallet.

Electronic Wallets Advantages and Disadvantages

An electronic wallet, sometimes called a “digital wallet” or “e-wallet,” is an electronic version of a payment card which is authorized to conduct transactions on your behalf. These wallets are usually on a mobile device, such as a smartphone, though desktops and laptops can hold an electronic as well.

Electronic wallets must be linked to specific debit or credit cards to operate properly. There may be a requirement to link the e-wallet to a bank account as well. Then, through the use of information and software, consumers can use their electronic wallet to pay for items instead of carrying a physical wallet to pay with a card.

There are several advantages and disadvantages of electronic wallets to examine if you’re thinking about embracing this technology.

List of the Advantages of Electronic Wallets

1. It offers more convenience for many consumers.

When you’re carrying an electronic wallet, you get to limit the number of cards you carry when you travel. You no longer have the requirement to carry a lot of cash with you either. All you need to do is tap your device to the payment receptacle, or have your mobile device scanned, to pay for the items you are purchasing. That means you’re no longer carrying a pocketful of items wherever you go.

2. It provides access to other types of cards.

Electronic wallets typically store credit cards and debit cards. They can be used for a wide variety of cards, however, if the provider is compatible with the wallet you are using. That means you can store rewards cards, loyalty cards, and even coupons within your digital wallet, allowing you to enjoy more of a paperless lifestyle.

3. It offers more security.

If you have a wad of cash in your pocket that gets lost, you have zero options available to you to recover your funds. Losing your credit cards means you must contact each lender to cancel each card, then have a new one issues. With an electronic wallet, the information is stored through a third-party provider. It’s locked behind your password or biometrics. Even if you lose your device, you’ll still have access to your e-wallet once you get a new device.

4. It can be used at most retailers and online stores.

Electronic wallets have become widely accepted within the past few years. Most locations that accept cards as a payment option will allow you to pay with your electronic wallet. Although there are still some locations that are using older processing technologies, which does limit some product or service access, the number of retailers who provide payment access in this manner continues to increase each year.

5. It requires users to authorize every transaction.

Electronic wallets function like a debit card when initiating a transaction. They require you to input your PIN to authorize payment. For devices with biometrics, a payment would require your fingerprint to authorize it. That gives you another layer of security against unauthorized purchases or the financial risks associated with identity theft.

6. It may offer access to new rewards.

Many electronic wallets offer incentives to encourage consumers to use them instead of traditional payment methods. You may find discounts apply to certain purchases, such as fuel, food, or travel. Some businesses may work with your e-wallet provide to offer specific discounts as well. That means you have the potential to save money without changing your spending habits. You’re just changing how you pay for those items.

7. It could help you with your budget.

Many electronic wallets can help you track your spending habits. Some may generate reports that show you specific categories of spending. You can also assign fixed budgets to specific cost categories to ensure that you’re not spending more than you should on certain items. If you have a big-ticket item to purchase, however, you can disable this feature to make sure there’s enough money available to make the payment.

List of the Disadvantages of Electronic Wallets

1. It is not fully available worldwide.

The number of retailers which accept payments from an electronic wallet depends on the actual wallet you choose. In December 2016, just 36% of retailers accepted Apple Pay. 34% of retailers accepted PayPal as a form of payment. Just 25% of retailers accepted MasterPass. About 2 million retailers in North America currently provide access to some form of mobile payment through an electronic wallet.

2. It still requires you to carry something.

Although an electronic wallet offers more convenience for many consumers, it doesn’t fully eliminate the requirement of carrying something with you. If you don’t have your mobile device on your person, then you have no way to complete a transaction. Because these wallets don’t store your identification and other needed items, you’re still forced to carry a traditional wallet or purse with you as well.

3. It requires your device to have a charge.

There’s also the disadvantage that an electronic wallet requires you to have a charged device to have it operate. If you’re carrying a traditional wallet, you won’t need to worry about how much battery life is left on your phone.

4. It doesn’t eliminate your security risks.

The security of your smartphone or mobile device is dependent on the settings you use. If you don’t have your device protected with some type of password, then someone could steal your device and potentially access the funds in your bank account or credit cards. There are definite security advantages to consider which make an e-wallet a beneficial technology, though it requires responsible management of it to maximize them.

5. It may charge you more to process payments.

Many of the electronic wallets which offer a rewards program will charge you a fee to transfer those rewards. You may be required to process payments in a specific way to access these benefits as well. When using the PayPal debit program, for example, consumers receive 1% cash back when their transaction is a standard signature credit transaction. Using a PIN through a digital wallet eliminates this benefit because you’re changing how the point-of-sale treats the transaction. If you spend $900 per month, you’d be losing over $100 each year for the convenience of this payment method.

6. It could encourage reckless spending.

When money is electronically-based instead of a physical item, some people struggle with their spending habits. The money doesn’t feel real, so proper budgeting doesn’t take place. If you are already struggling to maintain a budget with a traditional wallet, then an electronic wallet might make that issue even worse.

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JSON

JSON is an acronym for JavaScript Object Notation, is an open standard format, which is lightweight and text-based, designed explicitly for human-readable data interchange. It is a language-independent data format. It supports almost every kind of language, framework, and library.

In the early 2000s, JSON was initially specified by Douglas Crockford. In 2013, JSON was standardized as ECMA-404, and RCF 8259 was published in 2017.

JSON is an open standard for exchanging data on the web. It supports data structures like objects and arrays. So, it is easy to write and read data from JSON.

In JSON, data is represented in key-value pairs, and curly braces hold objects, where a colon is followed after each name. The comma is used to separate key-value pairs. Square brackets are used to hold arrays, where each value is comma-separated.

What is JSON

JSON stands for JavaScript Object Notation.

JSON is an open standard data-interchange format.

JSON is lightweight and self-describing.

JSON originated from JavaScript.

JSON is easy to read and write.

JSON is language independent.

JSON supports data structures such as arrays and objects.

Features of JSON

Simplicity

Openness

Self-Describing

Internationalization

Extensibility

Interoperability

Why do we use JSON?

Since JSON is an easy-to-use, lightweight language data interchange format in comparison to other available options, it can be used for API integration. Following are the advantages of JSON:

Less Verbose: In contrast to XML, JSON follows a compact style to improve its users' readability. While working with a complex system, JSON tends to make substantial enhancements.

Faster: The JSON parsing process is faster than that of the XML because the DOM manipulation library in XML requires extra memory for handling large XML files. However, JSON requires less data that ultimately results in reducing the cost and increasing the parsing speed.

Readable: The JSON structure is easily readable and straightforward. Regardless of the programming language that you are using, you can easily map the domain objects.

Structured Data: In JSON, a map data structure is used, whereas XML follows a tree structure. The key-value pairs limit the task but facilitate the predictive and easily understandable model.

JSON Data Types

Following are the most commonly used JSON data types.

· String

· Number

· Boolean

· Null

JSON Objects

In JSON, objects refer to dictionaries, which are enclosed in curly brackets, i.e., { }. These objects are written in key/value pairs, where the key has to be a string and values have to be a valid JSON data type such as string, number, object, Boolean or null. Here the key and values are separated by a colon, and a comma separates each key/value pair.

1. {"name" : "Jack", "employeeid" : 001, "present" : false}

JSON Arrays

In JSON, arrays can be understood as a list of objects, which are mainly enclosed in square brackets [ ]. An array value can be a string, number, object, array, boolean or null.

For example:

1. [{

2. "PizzaName" : "Country Feast",

3. "Base" : "Cheese burst",

4. "Toppings" : ["Jalepenos", "Black Olives", "Extra cheese", "Sausages", "Cherry tomatoes"],

5. "Spicy" : "yes",

6. "Veg" : "yes"

7. },

9. {

10. "PizzaName" : "Veggie Paradise",

11. "Base" : "Thin crust",

12. "Toppings" : ["Jalepenos", "Black Olives", "Grilled Mushrooms", "Onions", "Cherry tomatoes"],

13. "Spicy" : "yes",

14. "Veg" : "yes"

15. }

16. ]

In the above example, the object "Pizza" is an array. It contains five objects, i.e., PizzaName, Base, Toppings, Spicy, and Veg.

Output:

JSON Vs XML

JSON stands for JavaScript Object Notation, whereas XML stands for Extensive Markup Language. Nowadays, JSON and XML are widely used as data interchange formats, and both have been acquired by applications as a technique to store structured data.

JSON vs XML

Before knowing about the differences between JSON and XML, we should be aware of the definition of json and xml.

What is json?

JSON stands for JavaScript object notation. JSON has been derived from javascript, where javascript is a programming language. It was originally created to hold the structured data that could be used in javascript. JSON became so popular that it is used for data for all kinds of applications. It is the most popular way of sending the data for Web APIs.

Basic data types supported by json are:

Strings: Characters that are enclosed in single or double quotation marks.

Number: A number could be integer or decimal, positive or negative.

Booleans: The Boolean value could be either true or false without any quotation marks.

Null: Here, null means nothing without any quotation marks.

In addition to basic data types, json has arrays and objects.

A Sports and FIFA Sever Video

Arrays

Arrays are the lists that are represented by the square brackets, and the values have commas in between them. They can contain mix data types, i.e., a single array can have strings, Boolean, numbers.

For example:

Example 1: [1, 2, 7.8, 5, 9, 10];

Example 2: ["red", "yellow", "green"];

Example 3: [8, "hello", null, true];

In the above, example 1 is an array of numbers, example 2 is an array of strings, and example 3 is an array of mix data types.

Objects

Objects are JSON dictionaries that are enclosed in curly brackets. In objects, keys and values are separated by a colon ':', pairs are separated by comma. Keys and values can be of any type, but the most common type for the keys is a string.

For example: {"red" : 1, "yellow" : 2, "green" : 3};

Nesting

Nesting involves keeping the arrays and objects inside of each other. We can put the arrays inside objects, objects inside arrays, arrays inside arrays, etc. We can say that json file is a big object with lots of objects and arrays inside.

Example:

1. {

2. "song" :

3. {

4. "title" : "Hey Dude";

5. "artist": "The Beatles";

6. "musicians": ["John Lennon", "Paul McCratney", "Ringo Starr"];

7. }

8. }

In the above code, the song starts with a curly bracket. Therefore, a song is an object. It contains three key-value pairs wherein title, artist and musicians are the keys.'

What is XML?

XML stands for an extensible markup language. It is like HTML, where HTML stands for Hypertext Markup language. HTML is used for creating websites, whereas XML can be used for any kind of structured data.

XML has two ways of handling data, i.e., Tags and Attributes. The tags work as HTML. The start tags start with the <_> and end with the </_>. The start and end tags must match. The names must only be letters, numbers, and underscore, and the tag name must start with a letter only.

For example:

<title> Hello World </title>

Nested Tags

When we put the tag inside of another tag that creates the nested data.

For example:

1. <color>

2. <red> 1 </red>

3. <yellow> 2 </yellow>

4. <green> 3 </green>

5. </color>

As we can observe in the above code that inside the color tag, we have three more tags, i.e., red, yellow, and green.

Similarities between the json and XML.

Self-describing: Both json and xml are self-describing as both xml data and json data are human-readable text.

Hierarchical: Both json and xml support hierarchical structure. Here hierarchical means that the values within values.

Data interchange format: JSON and XML can be used as data interchange formats by many different programming languages.

Parse: Both the formats can be easily parsed.

Retrieve: Both formats can be retrieved by using HTTP requests. The methods used for retrieving the data are GET, PUT, POST.

#JSON #explain JSON #what is JSON #benifits of JSON #advantages of JSON #features of JSON #explain JSON and XML

Topology

Topology :

Topology defines the structure of the network of how all the components are interconnected to each other. There are two types of topology: physical and logical topology.

Physical topology is the geometric representation of all the nodes in a network.

Bus Topology

The bus topology is designed in such a way that all the stations are connected through a single cable known as a backbone cable.

Each node is either connected to the backbone cable by drop cable or directly connected to the backbone cable.

When a node wants to send a message over the network, it puts a message over the network. All the stations available in the network will receive the message whether it has been addressed or not.

The bus topology is mainly used in 802.3 (ethernet) and 802.4 standard networks.

The configuration of a bus topology is quite simpler as compared to other topologies.

The backbone cable is considered as a "single lane" through which the message is broadcast to all the stations.

The most common access method of the bus topologies is CSMA (Carrier Sense Multiple Access).

CSMA: It is a media access control used to control the data flow so that data integrity is maintained, i.e., the packets do not get lost. There are two alternative ways of handling the problems that occur when two nodes send the messages simultaneously.

CSMA CD: CSMA CD (Collision detection) is an access method used to detect the collision. Once the collision is detected, the sender will stop transmitting the data. Therefore, it works on "recovery after the collision".

CSMA CA: CSMA CA (Collision Avoidance) is an access method used to avoid the collision by checking whether the transmission media is busy or not. If busy, then the sender waits until the media becomes idle. This technique effectively reduces the possibility of the collision. It does not work on "recovery after the collision".

Advantages of Bus topology:

Low-cost cable: In bus topology, nodes are directly connected to the cable without passing through a hub. Therefore, the initial cost of installation is low.

Moderate data speeds: Coaxial or twisted pair cables are mainly used in bus-based networks that support upto 10 Mbps.

Familiar technology: Bus topology is a familiar technology as the installation and troubleshooting techniques are well known, and hardware components are easily available.

Limited failure: A failure in one node will not have any effect on other nodes.

Disadvantages of Bus topology:

Extensive cabling: A bus topology is quite simpler, but still it requires a lot of cabling.

Difficult troubleshooting: It requires specialized test equipment to determine the cable faults. If any fault occurs in the cable, then it would disrupt the communication for all the nodes.

Signal interference: If two nodes send the messages simultaneously, then the signals of both the nodes collide with each other.

Reconfiguration difficult: Adding new devices to the network would slow down the network.

Attenuation: Attenuation is a loss of signal leads to communication issues. Repeaters are used to regenerate the signal.

Ring Topology

Token passing: It is a network access method in which token is passed from one node to another node.

Token: It is a frame that circulates around the network.

Working of Token passing

A token moves around the network, and it is passed from computer to computer until it reaches the destination.

The sender modifies the token by putting the address along with the data.

The data is passed from one device to another device until the destination address matches. Once the token received by the destination device, then it sends the acknowledgment to the sender.

In a ring topology, a token is used as a carrier.

Advantages of Ring topology:

Network Management: Faulty devices can be removed from the network without bringing the network down.

Product availability: Many hardware and software tools for network operation and monitoring are available.

Cost: Twisted pair cabling is inexpensive and easily available. Therefore, the installation cost is very low.

Reliable: It is a more reliable network because the communication system is not dependent on the single host computer.

Disadvantages of Ring topology:

Difficult troubleshooting: It requires specialized test equipment to determine the cable faults. If any fault occurs in the cable, then it would disrupt the communication for all the nodes.

Failure: The breakdown in one station leads to the failure of the overall network.

Reconfiguration difficult: Adding new devices to the network would slow down the network.

Delay: Communication delay is directly proportional to the number of nodes. Adding new devices increases the communication delay.

Star Topology

Star topology is an arrangement of the network in which every node is connected to the central hub, switch or a central computer.

The central computer is known as a server, and the peripheral devices attached to the server are known as clients.

Coaxial cable or RJ-45 cables are used to connect the computers.

Hubs or Switches are mainly used as connection devices in a physical star topology.

Star topology is the most popular topology in network implementation.

Advantages of Star topology

Efficient troubleshooting: Troubleshooting is quite efficient in a star topology as compared to bus topology. In a bus topology, the manager has to inspect the kilometers of cable. In a star topology, all the stations are connected to the centralized network. Therefore, the network administrator has to go to the single station to troubleshoot the problem.

Network control: Complex network control features can be easily implemented in the star topology. Any changes made in the star topology are automatically accommodated.

Limited failure: As each station is connected to the central hub with its own cable, therefore failure in one cable will not affect the entire network.

Familiar technology: Star topology is a familiar technology as its tools are cost-effective.

Easily expandable: It is easily expandable as new stations can be added to the open ports on the hub.

Cost effective: Star topology networks are cost-effective as it uses inexpensive coaxial cable.

High data speeds: It supports a bandwidth of approx 100Mbps. Ethernet 100BaseT is one of the most popular Star topology networks.

Disadvantages of Star topology

A Central point of failure: If the central hub or switch goes down, then all the connected nodes will not be able to communicate with each other.

Cable: Sometimes cable routing becomes difficult when a significant amount of routing is required.

Tree topology

Tree topology combines the characteristics of bus topology and star topology.

A tree topology is a type of structure in which all the computers are connected with each other in hierarchical fashion.

The top-most node in tree topology is known as a root node, and all other nodes are the descendants of the root node.

There is only one path exists between two nodes for the data transmission. Thus, it forms a parent-child hierarchy.

Advantages of Tree topology

Support for broadband transmission: Tree topology is mainly used to provide broadband transmission, i.e., signals are sent over long distances without being attenuated.

Easily expandable: We can add the new device to the existing network. Therefore, we can say that tree topology is easily expandable.

Easily manageable: In tree topology, the whole network is divided into segments known as star networks which can be easily managed and maintained.

Error detection: Error detection and error correction are very easy in a tree topology.

Limited failure: The breakdown in one station does not affect the entire network.

Point-to-point wiring: It has point-to-point wiring for individual segments.

Disadvantages of Tree topology

Difficult troubleshooting: If any fault occurs in the node, then it becomes difficult to troubleshoot the problem.

High cost: Devices required for broadband transmission are very costly.

Failure: A tree topology mainly relies on main bus cable and failure in main bus cable will damage the overall network.

Reconfiguration difficult: If new devices are added, then it becomes difficult to reconfigure.

Mesh topology

Mesh technology is an arrangement of the network in which computers are interconnected with each other through various redundant connections.

There are multiple paths from one computer to another computer.

It does not contain the switch, hub or any central computer which acts as a central point of communication.

The Internet is an example of the mesh topology.

Mesh topology is mainly used for WAN implementations where communication failures are a critical concern.

Mesh topology is mainly used for wireless networks.

Mesh topology can be formed by using the formula: Number of cables = (n*(n-1))/2;

Where n is the number of nodes that represents the network.

Mesh topology is divided into two categories:

Fully connected mesh topology

Partially connected mesh topology

Full Mesh Topology: In a full mesh topology, each computer is connected to all the computers available in the network.

Partial Mesh Topology: In a partial mesh topology, not all but certain computers are connected to those computers with which they communicate frequently.

Advantages of Mesh topology:

Reliable: The mesh topology networks are very reliable as if any link breakdown will not affect the communication between connected computers.

Fast Communication: Communication is very fast between the nodes.

Easier Reconfiguration: Adding new devices would not disrupt the communication between other devices.

Disadvantages of Mesh topology

Cost: A mesh topology contains a large number of connected devices such as a router and more transmission media than other topologies.

Management: Mesh topology networks are very large and very difficult to maintain and manage. If the network is not monitored carefully, then the communication link failure goes undetected.

Efficiency: In this topology, redundant connections are high that reduces the efficiency of the network.

Hybrid Topology

The combination of various different topologies is known as Hybrid topology.

A Hybrid topology is a connection between different links and nodes to transfer the data.

When two or more different topologies are combined together is termed as Hybrid topology and if similar topologies are connected with each other will not result in Hybrid topology. For example, if there exist a ring topology in one branch of ICICI bank and bus topology in another branch of ICICI bank, connecting these two topologies will result in Hybrid topology.

Advantages of Hybrid Topology

Reliable: If a fault occurs in any part of the network will not affect the functioning of the rest of the network.

Scalable: Size of the network can be easily expanded by adding new devices without affecting the functionality of the existing network.

Flexible: This topology is very flexible as it can be designed according to the requirements of the organization.

Effective: Hybrid topology is very effective as it can be designed in such a way that the strength of the network is maximized and weakness of the network is minimized.

Disadvantages of Hybrid topology

Complex design: The major drawback of the Hybrid topology is the design of the Hybrid network. It is very difficult to design the architecture of the Hybrid network.

Costly Hub: The Hubs used in the Hybrid topology are very expensive as these hubs are different from usual Hubs used in other topologies.

Costly infrastructure: The infrastructure cost is very high as a hybrid network requires a lot of cabling, network devices, etc.

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Bug

Bug in Software Testing

In this chapter, we will learn about defect/bug in software testing and why it occurs, basic terminology of a defect, and bug tracking tool.

What is a bug in software testing?

The Bug is the informal name of defects, which means that software or application is not working as per the requirement.

In software testing

, a software bug can also be issue, error, fault, or failure. The bug occurred when developers made any mistake or error while developing the product.

While testing the application or executing the test cases, the test engineer may not get the expected result as per the requirement. And the bug had various names in different companies such as error, issues, problem, fault, and mistake, etc.

Basic terminology of defect

Let see the different terminology of defect:

Defect

Bug

Error

Issue

Mistakev

Failurev

Why defect/bug occur?

In software testing, the bug can occur for the following reasons:

Wrong coding

Missing coding

Extra coding

Wrong coding

Wrong coding means improper implementation.

For example: Suppose if we take the Gmail application where we click on the "Inbox" link, and it navigates to the "Draft" page, this is happening because of the wrong coding which is done by the developer, that's why it is a bug.

Missing coding

Here, missing coding means that the developer may not have developed the code only for that particular feature.

For example: if we take the above example and open the inbox link, we see that it is not there only, which means the feature is not developed only.

Extra coding

Here, extra coding means that the developers develop the extra features, which are not required according to the client's requirements.

For example:

Suppose we have one application form wherein the Name field, the First name, and Last name textbox are needed to develop according to the client's requirement.

But, the developers also develop the "Middle name" textbox, which is not needed according to the client's requirements as we can see in the below image:

If we develop an extra feature that is not needed in the requirement, it leads to unnecessary extra effort. And it might also happen that adding up the extra feature affects the other elements too.

Bug tracking tool

We have various types of bug tracking tools available in software testing that helps us to track the bug, which is related to the software or the application.

Some of the most commonly used bug tracking tools are as follows:

Jira

Bugzilla

Redmine

Mantis

Backlog

Jira

Jira is one of the most important bug tracking tools. Jira is an open-source tool that is used for bug tracking, project management, and issue tracking in manual testing

Jira includes different features like reporting, recording, and workflow. In Jira, we can track all kinds of bugs and issues, which are related to the software and generated by the test engineer.

Bugzilla

Bugzilla is another important bug tracking tool, which is most widely used by many organizations to track the bugs.

Bugzilla

is an open-source tool, which is used to help the customer, and the client to maintain the track of the bugs.

It is also used as a test management tool because, in this, we can easily link other test case management tools such as ALM, quality Centre, etc.

Bugzilla supports various operating systems such as Windows, Linux, and Mac.

Bugzilla has some features which help us to report the bug easily:

A bug can be list in multiple formats

Email notification controlled by user preferences.

Advanced searching capabilities

Excellent security

Time tracking

Redmine

It is an open-source tool which is used to track the issues and web-based project management tool. Redmine tool is written in Ruby programing language and also compatible with multiple databases like MySQL, Microsoft SQL, and SQLite.

While using the Redmine tool, users can also manage the various project and related subprojects.

Some of the common characteristics of Redmine tools are as follows:

Flexible role-based access control

Time tracking functionality

A flexible issue tracking system

Feeds and email notification

Multiple languages support (Albanian, Arabic, Dutch, English, Danish and so on)

MantisBT

MantisBT stands for Mantis Bug Tracker. It is a web-based bug tracking system, and it is also an open-source tool.

MantisBT is used to follow the software defects. It is executed in the PHP

programing language.

Some of the common features of MantisBT are as follows:

Full-text search

Audit trails of changes made to issues

Revision control system integration

Revision control of text fields and notes

Notifications

Plug-ins

Graphing of relationships between issues

Backlog

The backlog is widely used to manage the IT projects and track the bugs. It is mainly built for the development team for reporting the bugs with the complete details of the issues, comments. Updates and change of status. It is a project management software.

Features of backlog tool are as follows:

Gantt and burn down charts

It supports Git and SVN repositories

IP access control

Support Native iOS and Android apps

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Software Development Kit

Software Development Kit :

SDK stands for software development kit (sometimes called a devkit). As the name suggests, it’s a set of tools and instructions developers use to build apps. SDKs save developers from having to do every tedious bit of coding themselves. They help standardize the development, so apps can work more easily on different hardware, operating systems, and in cooperation with other apps.

So, why does this matter if you’re not a software developer? Because your app’s architecture is directly related to its business value, and when you choose what components to use (Stripe vs. PayPal for payments, for example), your choice should be informed by SDKs. Here, we’re providing a basic rundown of what SDKs are, how they work, and how to compare them by quality.

Software Development Kit (SDK) Definition and Examples

An SDK is a toolkit that app developers use to build apps using some prebuilt components instead of having to build each of those components themselves. SDKs are designed to work with specific operating systems, hardware, or computing languages.

Here’s a real-world analogy — if you’re trying to build a bookshelf, an SDK would be everything in the box you get from IKEA: prebuilt parts, tools, and instructions on how to put it all together. To build a desk without an SDK, you’d have to go into the forest and chop down your own lumber using an ax you built yourself.

For example, if you’re creating a mobile app, you’ll need to download Apple’s iOS SDK. This gives you access to whichever iPhone tools you want to use in your app, like connecting to the camera, the Siri interface, or enabling push notifications. Likewise, if you want to implement Auth0’s platform on both your mobile and web apps, you’d download the iOS SDK, Android SDK, and web SDK.

What’s in an SDK

Virtually all SDKs contain a few basic ingredients:

Code libraries: This is the raw code that developers plug in to make the app do what they want it to do.

Application programming interfaces (APIs): These allow the app to easily connect to other services (more on this later).

Integrated development environment (IDE): This is the interface through which developers do their programming. It includes a compiler, which translates the high-level programming language of the SDK’s source code into a lower-level language that can be used to build applications.

Documentation: These are the instructions that explain how developers should use the code. Clear, thorough documentation is an important criterion for a good SDK.

A debugger: Debugging automatically corrects minor errors, smoothing out the app development process.

Code samples: These get developers started by giving them some examples of the code in action and helping them use it in simple ways.

Some SDKs also include tutorials and other support tools.

Types of SDKs

Most apps are built with a variety of SDKs; for example, a 2019 study found that the average Android app uses 18.2 SDKs. Some SDKs optimize an app for a specific device or operating system, and some let developers insert various tools.

SDKs by hardware: SDKs aren’t just for web and mobile apps; they’re also used for programming in the Internet of Things (IoT). So if you purchase a set of solar panels, for example, the hardware provider might include an SDK, so developers can program them as desired.

Mobile device operating system: As we mentioned, designing an app that works on both Android and Apple phones requires an SDK for each.

Programming language for web apps: Developers need SDKs that let them build web apps in the programming language they choose, like Python, Ruby, JavaScript, or PHP.

Open source SDKs: These SDKs are free to use and invite developers to modify them as they choose. This can confer advantages when it comes to customizability but may also introduce security risks.

Proprietary SDKs: Unlike open source SDKs, proprietary or commercial SDKs require a license to use and don’t permit developers to change the source code.

SDKs Versus APIs

It’s easy to be confused by the difference between an SDK and an API, but the distinction is both simple and crucial.

APIs are the parts of code that communicate between two pieces of software. So, if you’re building a ride-sharing app, you need APIs that connect it to a user’s phone and messaging capabilities, payment platform, and GPS. All these elements might have different back ends, but an API lets them communicate and provide a seamless user experience.

The majority of SDKs contain APIs, so developers can build apps that are designed for easy connectivity. Without APIs, connecting apps is a little like that famous scene from Apollo 13.

But it’s not as simple as saying that APIs are components of SDKs since you can use an API without an SDK. And in some cases, developers have to choose between using an SDK or an API to handle integration with a particular service. The advantage of an SDK is that it’s simpler and faster to integrate (like the IKEA desk; most of the work is already done for you). The advantage of an API is that it’s leaner (not full of code libraries for functionalities you don’t need), and there’s more room for customization (if you build your own desk, you can design it to whatever dimensions you’d like).

The Elements of a Good SDK

If you’re building an app, chances are you’ll use SDKs for some of your functionality, like payment, messaging, or authentication. Those components are extremely difficult for developers to build in-house, and any errors can lead to major security issues. When you’re choosing which provider to use for those services, you’ll compare prices and features, but you should also be comparing their SDKs.

Here’s what to look for in a good SDK:

Lightweight: You want an SDK that does what you need it to do with as little code as possible. Otherwise, a mobile app can eat up too much space on a user’s phone, and the apps will run more slowly. If you’re replatforming or rearchitecting a legacy app, it’s worth looking at how much code your existing solutions use and whether an SDK would be more lightweight. For example, Auth0 customer Kiva was able to eliminate over 20,000 lines of legacy code by switching to Auth0 for authentication.

Good documentation: Two SDKs could be virtually identical, but if one has thorough documentation that shows developers how to use it, and the other leaves them on their own, then they’re hardly equal. In fact, this issue is one of the most common reasons Auth0 customers give for choosing us over our competitors.

Customizable: Some SDKs are resistant to customization, meaning you can only implement them with their out-of-the-box settings. That’s an issue if your developers want to tweak a product for their unique needs or insert original branding or graphics.

Secure: It’s essential to use SDKs that come from trusted sources to ensure that you’re not unwittingly inserting malicious or otherwise unwanted code into your app. In SafeDK’s report, “58% of the examined apps still have at least 1 SDK that accesses private user data.” In the age of data privacy laws, this collection may get your app into legal hot water.

Easy to use: A good SDK should provide tutorials and sample code and also let developers connect to a trusted community or support services if they run into any problems.

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Data visualization

Data Visualization:

Data visualization is a graphical representation of quantitative information and data by using visual elements like graphs, charts, and maps.

Data visualization convert large and small data sets into visuals, which is easy to understand and process for humans.

Data visualization tools provide accessible ways to understand outliers, patterns, and trends in the data.

In the world of Big Data, the data visualization tools and technologies are required to analyze vast amounts of information.

Data visualizations are common in your everyday life, but they always appear in the form of graphs and charts. The combination of multiple visualizations and bits of information are still referred to as Infographics.

Data visualizations are used to discover unknown facts and trends. You can see visualizations in the form of line charts to display change over time. Bar and column charts are useful for observing relationships and making comparisons. A pie chart is a great way to show parts-of-a-whole. And maps are the best way to share geographical data visually.

Today's data visualization tools go beyond the charts and graphs used in the Microsoft Excel spreadsheet, which displays the data in more sophisticated ways such as dials and gauges, geographic maps, heat maps, pie chart, and fever chart.

Data Visualization Effective:

Effective data visualization are created by communication, data science, and design collide. Data visualizations did right key insights into complicated data sets into meaningful and natural.

American statistician and Yale professor Edward Tufte believe useful data visualizations consist of ?complex ideas communicated with clarity, precision, and efficiency.

To craft an effective data visualization, you need to start with clean data that is well-sourced and complete. After the data is ready to visualize, you need to pick the right chart.

After you have decided the chart type, you need to design and customize your visualization to your liking. Simplicity is essential - you don't want to add any elements that distract from the data.

History of Data Visualization

The concept of using picture was launched in the 17th century to understand the data from the maps and graphs, and then in the early 1800s, it was reinvented to the pie chart.

Several decades later, one of the most advanced examples of statistical graphics occurred when Charles Minard mapped Napoleon's invasion of Russia. The map represents the size of the army and the path of Napoleon's retreat from Moscow - and that information tied to temperature and time scales for a more in-depth understanding of the event.

Computers made it possible to process a large amount of data at lightning-fast speeds. Nowadays, data visualization becomes a fast-evolving blend of art and science that certain to change the corporate landscape over the next few years.

Importance of Data Visualization

Data visualization is important because of the processing of information in human brains. Using graphs and charts to visualize a large amount of the complex data sets is more comfortable in comparison to studying the spreadsheet and reports.

Data visualization is an easy and quick way to convey concepts universally. You can experiment with a different outline by making a slight adjustment.

Data visualization have some more specialties such as:

Data visualization can identify areas that need improvement or modifications.

Data visualization can clarify which factor influence customer behavior.

Data visualization helps you to understand which products to place where.

Data visualization can predict sales volumes.

Data visualization tools have been necessary for democratizing data, analytics, and making data-driven perception available to workers throughout an organization. They are easy to operate in comparison to earlier versions of BI software or traditional statistical analysis software. This guide to a rise in lines of business implementing data visualization tools on their own, without support from IT.

Why Use Data Visualization?

1. To make easier in understand and remember.

2. To discover unknown facts, outliers, and trends.

3. To visualize relationships and patterns quickly.

4. To ask a better question and make better decisions.

5. To competitive analyze.

6. To improve insights.

Data Visualization Tools :

There are tools which help you to visualize all your data in a few minutes. They are already there; only you need to do is to pick the right data visualization tool as per your requirements.

Data visualization allows you to interact with data. Google, Apple, Facebook, and Twitter all ask better a better question of their data and make a better business decision by using data visualization.

Here are the top 10 data visualization tools that help you to visualize the data:

1. Tableau

Tableau is a data visualization tool. You can create graphs, charts, maps, and many other graphics.

A tableau desktop app is available for visual analytics. If you don't want to install tableau software on your desktop, then a server solution allows you to visualize your reports online and on mobile.

A cloud-hosted service also is an option for those who want the server solution but don't want to set up manually. The customers of Tableau include Barclays, Pandora, and Citrix.

2. Infogram

Infogram is also a data visualization tool. It has some simple steps to process that:

1. First, you choose among many templates, personalize them with additional visualizations like maps, charts, videos, and images.

2. Then you are ready to share your visualization.

3. Infogram supports team accounts for journalists and media publishers, branded designs of classroom accounts for educational projects, companies, and enterprises.

An infogram is a representation of information in a graphic format designed to make the data easily understandable in a view. Infogram is used to quickly communicate a message, to simplify the presentation of large amounts of the dataset, to see data patterns and relationships, and to monitor changes in variables over time.

Infogram abounds in almost any public environment such as traffic signs, subway maps, tag clouds, musical scores, and weather charts, among a huge number of possibilities.

3. Chartblocks

Chartblocks is an easy way to use online tool which required no coding and builds visualization from databases, spreadsheets, and live feeds.

Your chart is created under the hood in html5 by using the powerful JavaScript library D3.js. Your visualizations is responsive and compatible with any screen size and device. Also, you will be able to embed your charts on any web page, and you can share it on Facebook and Twitter.

4. Datawrapper

Datawrapper is an aimed squarely at publisher and journalist. The Washington Post, VOX, The Guardian, BuzzFeed, The Wall Street Journal and Twitter adopts it.

Datawrapper is easy visualization tool, and it requires zero codings. You can upload your data and easily create and publish a map or a chart. The custom layouts to integrate your visualizations perfectly on your site and access to local area maps are also available.

5. Plotly

Plotly will help you to create a slick and sharp chart in just a few minutes or in a very short time. It also starts from a simple spreadsheet.

The guys use Plotly at Google and also by the US Air Force, Goji and The New York University.

Plotly is very user-friendly visualization tool which is quickly started within a few minutes. If you are a part of a team of developers that wants to have a crack, an API is available for JavaScript and Python languages.

6. RAW

RAW creates the missing link between spreadsheets and vector graphics on its home page.

Your Data can come from Google Docs, Microsoft Excel, Apple Numbers, or a simple comma-separated list.

Here the kicker is that you can export your visualization easily and have a designer to make it look sharp. RAW is compatible with Inkscape, Adobe Illustrator, and Sketch. RAW is very easy to use and get quick results.

7. Visual.ly

Visual.ly is a visual content service. It has a dedicated data visualization service and their impressive portfolio that includes work for Nike, VISA, Twitter, Ford, The Huffington post, and the national geographic.

By a streamlined online process, you can find entire outsource your visualizations to a third-party where you describe your project and connected with a creative team that will stay with you for the entire duration of the project.

Visual.ly sends you an email notification for all the event you are hitting, and also it will give you constant feedback to your creative team. Visual.ly offer their distribution network for showcasing your project after it's completed.

8. D3.js

D3.js is a best data visualization library for manipulating documents. D3.js runs on JavaScript, and it uses CSS, html, and SVG. D3.js is an open-source and applies a data-driven transformation to a webpage. It's only applied when data is in JSON and XML file.

D3.js emphasis on web standards gives you the full capabilities of modern browsers without tying yourself to a single framework and combining powerful visualization components.

D3.js is as powerful as it is a cutting-edge library, so it comes with no pre-built charts and only IE9+ supports this library.

9. Ember Charts

Ember charts are based on the ember.js and D3.js framework, and it uses the D3.js under the hood. It also applied when the data is in JSON and XML file.

It includes a bar, time series, pie, and scatter charts which are easy to extend and modify. These chart components represent our thoughts on best practices in chart presentation and interactivity.

The team behind Ember Charts is also the same that created Ember.js. It puts a lot of focus on best practices and interactivity. Error handling is very graceful, and your app will not crash after finding irrelevant data or corrupt data.

10. NVD3

NVD3 is a project that attempts to build reusable charts and components. This project is to keeps all your charts neat and customizable.

NDV3 is a simpler interface on the top of the D3.js and keeps all of its powerful features under the hood.

The front end engineers develop NDV3, and they use their insight into charting technology. This charting technology is used to provide powerful analytics to clients in the financial industry.

Benefits of Data Visualization Tools

1. Effective Data Visualization is the key to unlock Big Data. It can solve any data inefficiencies and easily and instantly absorb vast amounts of data presented in visual formats.

2. By enabling users to understand data rapidly, visualization can quickly increase the speed of decision making as well. Any business must make fast decisions and not get bogged down by inefficiencies. Timely actions result in averting any losses and benefit from any market condition.

3. A big reveal for any differences in the trends and patterns is vital for any business’s survival. It is critical to know what is causing increased losses or what is required to maximize gains.

4. Visualization helps identify errors and inaccuracies in data quickly.

5. Companies can utilize visualization to access real-time information and assist in management functions in a significant manner. Decision-makers can benefit from on-demand data and use visualization to increase the effectiveness of operations and improve productivity.

6. It promotes storytelling in the most compelling way. Visuals are used in the most meaningful way to convey the right message to the audience.

7. Data visualization assists in exploring business insights to achieve business goals in the right direction. It helps to correlate the data from the visual representations or graphical representations. It allows for fast analysis and instantly digests critical metrics.

8. It enables enterprises to stay on top of their game by discovering the latest trends through data visualization tools.

9. Without data visualization, businesses would have to spend tons of their time customizing reports and modifying dashboards, replying to ad hoc requests, etc. The benefits of Data visualization tools optimize and instantly retrieve data via tailor-made reports, which significantly cuts down on employee time.

#Data visualization #explain Data visualization #what is Data visualization #advantages of Data visualization #benifits of Data visualization

BIOS

BIOS:

BIOS is a program, stands for basic input/output system, which is stored in nonvolatile memory like ROM (Read Only Memory) or flash memory that allows you to set up and access your computer system at the greatest basic level. Although there is no need for most people to mess with the BIOS on a computer, it can be better to know about BIOS

. It is found on motherboards that are a pre-installed program on Windows-based computers that executes when a computer is powered up. Before an OS is loaded, the CPU

accesses the basic input/output system (BIOS). Then, the next function of BIOS is to examine all the hardware connections and detects all your devices.

The main function of BIOS is to set up hardware and start an OS, and it contains generic code that is needed to control display screens, the keyboard, and other functions. The BIOS is built-in software that manages the hard drives and cannot live on one. It cannot reside in the RAM (Random Access Memory)

as it is accessible before the computer system boots up. Actually, it lives on the ROM

of the computer system, and mainly it is located on EPROM (erasable programmable read-only memory) chip. Therefore, the CPU

accesses the EPROM when you turn on the computer and provides control to the BIOS.

The primary intention of designing the BIOS system is to function with numerous devices that led to making a complimentary system chipset. There are some functions contained by the BIOS library that operates and controls system peripherals, and they can be initiated through external software.

Users can perform different functions by using the BIOS user interface, which is discussed below:

Users can perform hardware configuration

They can select boot drives

They can set the system clock

The BIOS allows users to enable and disable certain system components

To BIOS user interface function, it provides set password prompts for secured access

The BIOS works as an intermediary between the I/O devices and the CPU and is used after the computer has booted up. The BIOS works as an intermediary between the I/O devices and the CPU and is used after the computer has booted up. Your operating system and programs do not need to know the details about the I/O devices connected to your system because of the BIOS. You can change these settings accordingly with the help of entering the BIOS setup at the time of your system starts up. Furthermore, if you want to access the BIOS setup, you can hold down the DELETE or F2 key when your computer starts up.

BIOS is stored in rewritable memory in some modern PCs, which allow information to be replaced or rewritten. Such content rewriting is executed with the help of a special program offered by system manufacturers.

BIOS Availability

The BIOS software is available in all modern computer motherboards. As the BIOS is a part of the motherboard; therefore, the BIOS's access and configuration on PCs are independent of any type of operating system. The BIOS is not dependent on anyone that means it does not matter which types of an operating system is running on the computer like Windows 7, Windows 8, Windows 10

, Windows XP, Linux

, Windows Vista, Unix, or no operating system at all, BIOS functions outside of the operating system environment.

What is included in a BIOS?

The directions to load basic computer hardware are included in BIOS software. A test is also included within it that is referred to as a POST (Power-On Self-Test). The POST helps the computer to boot up properly with verifying the computer meets requirements. Your computer produces various forms of beeps if the POST test fails at the time of test.

Functions of BIOS

The BIOS has different instructions that are required to load the hardware, and it is responsible for loading the operating system. The major functions of a Basic input/output system (BIOS) are discussed below:

BIOS Power on Self-Test (POST): It ensures the proper functioning of the computer hardware as it is a built-in diagnostic program that. In the system, it verifies the computer meets the necessary parts and functionality. POST does this function efficiently. It ensures that the computer is loading tasks successfully, such as the use of memory, a keyboard, and other parts when it starts up. If the POST test fails at the time of test, the computer provides a combination of beeps to display the error type, and the system continues to boot when the POST test is passed completely. Once the self-test has been passed, and the basic instructions have been loaded, the computer starts to load the OS from one of the connected drives to the system. The BIOS settings can also be changed by the computer users with the help of a configuration screen on the computer. The BIOS information can also be stored on the flash memory, which can be updated by computer users after releasing an update by vendors. BIOS actually can be located in between the external devices and the computer because its name describes that it is used for reading and writing to and hard disk and floppy disc, displaying values on the screen, reading the keystroke, etc.

Bootstrap Loader: The BIOS recognizes and locates the operating system when the POST running successfully. The program bootstrap loader is contained by BIOS, which searches and starts the OS boot program. When BIOS detects one, it transfers access to Operating System that is known as booting.

BIOS drivers: BIOS drivers are stored in the non-volatile memory, whose primary function is to supply basic computer hardware information.

BIOS Setup Utility Program: It is a configuration software, also known as CMOS setup, that allows users to configure hardware settings as well as device settings, time and date, computer password. The NVRAM, non-volatile memory, is used to store settings of memory, disk types, and information about the computer system; this information is not stored in the BIOS chip

The users run the BIOS setup program during the installation of a system and input the correct parameters. The CMOS (Complementary metal-oxide-semiconductor) is a required material to construct NVRAM. These CMOS chips store and maintain data on very low values of current. Therefore, the system's configurations are also called CMOS settings. With the help of using a capacitor, maintaining the battery backup, or by a battery built into the NVRAM chip, CMOS settings can be maintained. Additionally, a system clock is also included in this chip. The setting remains for a short period of time if there is no battery. And there is a need to reset the system. Through its BIOS set up program is protected as there is loss of BIOS password.

With computers, BIOS come in-built as firmware on a chip on the motherboard. In contrast, an operating system such as iOS or Windows can be installed by the user or pre-installed by the vendor or manufacturer.

When BIOS boots up a computer, it verifies the computer meets the necessary attachments to boot up. The files are contained by any piece of hardware that needs for a computer to start up, this piece of hardware is known as a boot device.

Different types of BIOS

The BIOS screen is seen by every PC user, it does not matter he knows it or not each time he turns on his computer system. The computer's manufacturer displays the screen is called the Basic Input/Output System (BIOS). The BIOS has mainly two types, which are as follows:

1. UEFI: The UEFI can accommodate 2.2 TB or larger drives, which stands for Unified Extensible Firmware Interface. It handles drives with the help of using the Master Boot Record instead of GPT technology, the more modern GUID Partition Table. Furthermore, Apple's Mac PCs have never used the BIOS.

2. Legacy BIOS: The Legacy BIOS was used in older motherboards to turn the PC on. Legacy BIOSes have limitations as they have no ability to handle or recognize drives bigger than 2.1 TB. However, it controls how the CPU and the components communicate with each other.

BIOS vs UEFI

Most probably, you will see UEFI rather than the BIOS in most modern computers. But what are the differences between both UEFI and BIOS? It can be difficult to differentiate both because they almost perform the same function. UEFI is the same as BIOS, stands for Unified Extensible Firmware Interface, and acts as an intermediate program between the hardware and the OS.

As compared to BIOS, UEFI offers more features and can be extensively customized. In order to load the operating system, it does not need a separate program of a bootloader. It has the ability to manage hard drives that can be exceeded two Terabytes as it offers native support GPT, and BIOS is unable to provide this.

Upgrading a BIOS

Often, it is discovered that when the computer needs to be upgraded with latest hardware, it does not support all the features of the latest hardware. It needs to be upgraded hardware like more memory, a larger hard drive, or a new video card. Upgrading the BIOS chip is an easier solution to this problem. Generally, to upgrade BIOS on the system, the files and information are available on the computer's or motherboard maker's Web site.

Unluckily, it is most important to know that upgrading the BIOS can be a drastic step. If you are going to upgrade the BIOS, you will be better to back up all of your data from the hard drive. Also, make sure there is a recovery jumper that makes you capable of recovering the original BIOS. Although upgrading the BIOS is trouble-free, it is possible for the by upgrading BIOS the system can be computer unusable, damage or destroy the BIOS chip.

A brief history of BIOS

The term BIOS (Basic Input/Output System) first appeared in the CP/M operating system in 1975 and was created by Gary Kildall. It was used to describe the machine-specific part of CP/M loaded during the boot time. These ideas were adopted by Microsoft DOS in the first versions of DOS, which included similar. The files used in CP/M were very close to COM and.SYS files.

The PC's BIOS was held on PROM or ROM chips that were placed on the computer's motherboard through the early 1990s. Some companies, such as Phoenix Technologies, reversed the BIOS originally proprietary to the IBM PC, creating compatible systems. Also, in the mid-1990s, the BIOS was shifted to being stored on EEPROM chips or flash drives on the computer, as to update the BIOS, and demand for complexity increased. In modern times, some computers can have the BIOS, which size can be more than 16 megabytes.

The System BIOS was divided by IBM into real- and protected-mode portions when the PS/2 machines were introduced. The real-mode portion was mainly responsible for offering compatibility with existing OS like DOS, that's why it's named was CBIOS, while new interfaces were provided by ABIOS that was especially ideal for multitasking operating systems such as OS/2.

BIOS security

BIOS security somewhere is a unique component of cybersecurity. However, there is still a need to manage it because there are various hackers who can run malicious code on the OS, which can be more harmful. In 2017, inside a motherboard's UEFI, how modern BIOS security flaws could enable ransomware programs it showed by security group Cylance. And other PCs get the benefit of BIOS vulnerabilities.

BIOS manufacturers

In the beginning, BIOS was fundamentally owned by IBM. However, IBM's original version was reverse-engineered by some other companies like Phoenix Technologies to create their own. For doing that, other companies have permission to create clones of the IBM PC by Phoenix. Also, an important thing that they can create non-IBM computers that work with BIOS. Compaq was one company that did this. In modern times, there are various manufacturers of the motherboard with BIOS chips; some are as follows:

Foxconn

AMI

Hewlett Packard (HP)

Ricoh

Asus

It may be very important to know about the motherboard manufacturer as users sometimes need to update their BIOS and chipset drivers. The operating system functions with other devices in the computer through the drivers. For example, a video card to the most recent versions. When you update drivers, the patch can cause recent BIOS-level security vulnerabilities, or computer performance can be improved.

#Bios #explain Bios #what is Bios #types of Bios #benifits of Bios #advantages of Bios #disadvantages of Bios #features of Bios

Ad hoc network

Ad hoc network :

A wireless ad hoc network (WANET) is a type of local area network (LAN) that is built spontaneously to enable two or more wireless devices to be connected to each other without requiring typical network infrastructure equipment, such as a wireless router or access point. When Wi-Fi networks are in ad hoc mode, each device in the network forwards data that is not intended for itself to the other devices.

Because the devices in the ad hoc network can access each other's resources directly through a basic peer-to-peer (P2P) wireless connection, central servers are unnecessary for functions such as file sharing or printing. In a WANET, a collection of devices, or nodes, is responsible for network operations, such as routing, security, addressing and key management.

Devices in the ad hoc network require a wireless network adapter or chip, and they need to be able to act as a wireless router when connected. When setting up a wireless ad hoc network, each wireless adapter must be configured for ad hoc mode instead of infrastructure mode. All wireless adapters need to use the same service set identifier (SSID) and wireless frequency channel number.

Instead of relying on a wireless base station to coordinate the flow of messages to each node in the network, the individual nodes in ad hoc networks forward packets to and from each other. Makeshift by nature, ad hoc wireless networks are useful where there is not a wireless structure built -- for example, if there aren't any access points or routers within range and cabling cannot be extended to reach the location where additional wireless communication is needed.

However, not all Wi-Fi networks are the same. In fact, Wi-Fi access points work in either ad hoc or infrastructure mode. Typically, Wi-Fi networks in infrastructure mode are created and managed using equipment such as Wi-Fi routers, wireless access points (WAPs) and wireless controllers. Ad hoc networks are also often short-lived networks created by a laptop or other device. The use of more sophisticated network protocols and network services found on infrastructure-based wireless networks usually are not suitable for ad hoc networks.

wireless ad hoc network :

Deciding when to employ ad hoc versus infrastructure mode depends on the use. A user who wants a wireless router to act as a permanent access point should choose infrastructure mode. But ad hoc mode might be a good option for a user setting up a temporary wireless network between a small number of devices.

Connecting devices to the internet using an ad hoc network.

Ad hoc networks are used frequently in new types of wireless engineering. They require minimal configuration and can be deployed quickly, which makes them suitable for emergencies, such as natural disasters or military conflicts. Thanks to the presence of dynamic and adaptive routing protocols, these networks can be configured quickly. These impromptu, on-demand networks are useful for putting together a small, inexpensive all-wireless LAN without the need for wireless infrastructure equipment. They also work well as a temporary fallback mechanism if equipment for an infrastructure mode network fails.

The following example shows one of the more popular uses for an ad hoc wireless network: connecting multiple wireless endpoints to the internet using an ad hoc intermediary device. Note that the intermediary device consists of a PC or laptop with a wired connection to the internet and a second wireless chip/antenna to connect other ad hoc wireless-capable devices to it for the purpose of sharing internet access.

Types of ad hoc wireless networks :

Types of WANETs vary by application need and use. Choosing a wireless ad hoc network type depends on the wireless equipment capabilities, physical environment and purpose of the communication.

MANET. A mobile ad hoc network involves mobile devices communicating directly with one another. A MANET is a network of wireless mobile devices without an infrastructure that are self-organizing and self-configuring. A MANET is sometimes referred to as an "on-the-fly" or "spontaneous network."

IMANETs. Internet-based mobile ad hoc networks support internet protocols, such as TCP/IP (Transmission Control Protocol/Internet Protocol) and User Datagram Protocol (UDP). The iMANET employs a network-layer routing protocol on each connected device to link mobile nodes and set up distributed routes automatically. IMANETs may also be used in the collection of sensor data for data mining for a variety of use cases, such as air pollution monitoring.

SPANs. Smartphone ad hoc networks employ existing hardware, such as Wi-Fi and Bluetooth, and software protocols built into a smartphone operating system (OS) to create P2P networks without relying on cellular carrier networks, wireless access points or other traditional network infrastructure equipment. Different from traditional hub-and-spoke networks, such as Wi-Fi Direct, SPANs support multi-hop relays. Multi-hop relay is the process of sending traffic from device A to device C using intermediary device B. Therefore, device A and C do not need to have a direct P2P connection established for traffic to reach its destination. And because SPANs are fully dynamic in nature, there is no notion of a group leader in this type of application and, thus, peers can join or leave without harming the network.

Vehicular ad hoc network. This network type involves devices in vehicles that are used for communicating between them and roadside equipment. An example is the in-vehicle safety and security system, OnStar.

Wireless mesh networks comprised of radio networks set up in a mesh topology, frequently consist of mesh clients, mesh routers and gateways. In mesh networking, the devices -- or nodes -- are connected so at least some, if not all, have many paths to other nodes. This creates many routes for information between pairs of users, increasing the resilience of the network if a node or connection fails. Wireless mesh networks are useful in situations where a temporary wireless network is required or in more permanent scenarios where network cabling cannot be run to create an infrastructure-based wireless network.

Other types of ad hoc wireless networks include wireless sensor networks, ad hoc smart home lighting, ad hoc streetlight networks, ad hoc networks of robots, disaster rescue ad hoc networks and hospital ad hoc networks. Wireless ad hoc networks also have a number of military applications, such as Army tactical MANETs, Air Force UAV (unmanned aerial vehicle) ad hoc networks and Navy ad hoc networks.

Wireless ad hoc networks have advantages and disadvantages. Although some Wi-Fi networking experts maintain that for small LANs, ad hoc networks don't require as much hardware and can be less costly to build, others assert that large numbers of devices can be challenging to manage without a larger, more concrete infrastructure.

Advantages of a WANET :

Ad hoc mode can be easier to set up than infrastructure mode when just connecting two devices without requiring a centralized access point. For example, if a user has two laptops and is in a hotel room without Wi-Fi, they can be connected directly in ad hoc mode to create a temporary Wi-Fi network without a router. The Wi-Fi Direct standard -- a specification that allows devices certified for Wi-Fi Direct to exchange data without an internet connection or a wireless router -- also builds on ad hoc mode and enables devices to communicate directly over Wi-Fi signals.

Other benefits of wireless ad hoc networks include the following:

· Because ad hoc networks do not require infrastructure hardware such as access points or wireless routers, these networks provide a low-cost way of direct client-to-client communication.

· Ad hoc networks are easy to configure and offer an effective way to communicate with devices nearby when time is of the essence and running cabling is not feasible.

· Ad hoc networks are often secured to protect against attacks, as their temporary, often impromptu qualities can make them vulnerable to security threats.

· An ad hoc network linking a small number of devices might be a more practical choice compared to a traditional infrastructure-based network that can connect many more devices.

Disadvantages of ad hoc networks :

One major drawback of wireless ad hoc networking is that some Wi-Fi-enabled technology, including certain Android devices, wireless printers and custom IoT sensors, don't support ad hoc mode because of its limitations and will only connect to networks in infrastructure mode by default. In some cases, third-party software can be installed on endpoint devices to enable ad hoc communications.

Infrastructure mode is a better option than ad hoc mode for setting up a larger and more permanent network that can support far more endpoints. Wireless routers that serve as access points typically have higher-power wireless radios and antennas that provide coverage of a wider area. Ad hoc networks often suffer from poor wireless communication range issues, as antennas built into endpoints were not designed to be as powerful as purpose-built WAPs.

Ad hoc networks also do not scale well. As the number of devices in an ad hoc network increases, it becomes harder to manage because there is not a central device through which all traffic flows. When several devices are connected to the ad hoc network, more wireless interference will occur, as each device must establish a direct P2P connection to each of the other devices, instead of going through a single access point in a hub-and-spoke architecture. When a device is out of range of a device to which it needs to connect, it will pass the data through other devices on the way; this is slower than passing it through a single access point.

Other disadvantages of ad hoc wireless networks include the following:

· Devices in an ad hoc network cannot disable SSID broadcasting like devices in infrastructure mode can. As a result, attackers can find and connect to an ad hoc device if they are within signal range.

· Security options are limited due to a lack of network infrastructure services, such as access to a RADIUS (remote authentication dial-in user service) server for authentication purposes.

· Wireless ad hoc networks cannot bridge wired LANs or to the internet without installing a special-purpose network gateway.

· Devices can only use the internet if one of them is connected to and sharing it with the others. When internet sharing is enabled, the client performing this function may face performance problems, especially if there are many interconnected devices.

· Ad hoc mode requires the use of more endpoint system resources, as the physical network layout changes when devices are moved around; in contrast, an access point in infrastructure mode typically remains stationary from an end-device perspective.

Despite the disadvantages, wireless ad hoc networks remain a viable option for many personal and enterprise use cases. As long as network administrators understand the communication capabilities of a WANET -- and if those capabilities can fulfil a specific need -- building an ad hoc network is a quick and fairly painless way to connect two or more devices.

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Digital Signature

Digital Signature:

Digital signatures function similarly to digital “fingerprints.” The digital signature, which takes the form of a coded message, securely links a signer with a document in a recorded transaction. Digital signatures rely on a universally accepted format known as Public Key Infrastructure (PKI) to ensure enhanced security. They are a subset of electronic signature technology (eSignature).

It is a mathematical scheme for demonstrating the authenticity of digital messages or documents. It is a virtual fingerprint that is unique to a person and is used to identify signers and secure data in digital documents. It is a type of electronic signature that ensures compliance with legal regulations by providing the validity and authenticity of a digital document and the signer’s identity. Digital signatures can provide proof of origin, time, identity, and status of a digital document. A signature confirms that the data emanated from the signer and has not been tampered with during transit.

A digital signature is a type of electronic signature where a mathematical algorithm is routinely used to validate the authenticity and integrity of a message (e.g., an email, a credit card transaction, or a digital document). Digital signatures create a virtual fingerprint that is unique to an individual or entity and are used to identify users and protect the information in digital messages or documents and ensure no distortion occurs when in transit between signer and receiver. In emails, the email as a whole also becomes a part of the digital signature. Digital signatures are significantly more reliable and secure than other forms of electronic signatures.

Why are digital signatures considered secure:

Digital signatures work using public-key cryptography. Public key cryptography is a cryptographic method that uses a key pair system, private and public. The private key encrypts the data and is available only to the signer. The public key decrypts the data pertaining to the digital document and is given to the receiver. However, both parties must have a registered digital certificate from an issuing certificate authority to connect the signer and their signature. Public key cryptography ensures the security, accuracy, and authenticity of the document. Encryption is the process of encoding data send to the receiver in a form that can only be decoded by the receiver. Authentication is the process of validating the information from the sender is genuine and has not been altered in transit.

Just like every handwritten signature is unique, every signer is given a unique digital identity from a trusted service provider. When the signer signs a document, the signer’s identity is validated and the signature is encrypted using public key infrastructure technology.

Importance of Digital Signature

Out of all cryptographic primitives, the digital signature using public key cryptography is considered as very important and useful tool to achieve information security.

Apart from ability to provide non-repudiation of message, the digital signature also provides message authentication and data integrity. Let us briefly see how this is achieved by the digital signature −

· Message authentication − When the verifier validates the digital signature using public key of a sender, he is assured that signature has been created only by sender who possess the corresponding secret private key and no one else.

· Data Integrity − In case an attacker has access to the data and modifies it, the digital signature verification at receiver end fails. The hash of modified data and the output provided by the verification algorithm will not match. Hence, receiver can safely deny the message assuming that data integrity has been breached.

· Non-repudiation − Since it is assumed that only the signer has the knowledge of the signature key, he can only create unique signature on a given data. Thus the receiver can present data and the digital signature to a third party as evidence if any dispute arises in the future.

By adding public-key encryption to digital signature scheme, we can create a cryptosystem that can provide the four essential elements of security namely − Privacy, Authentication, Integrity, and Non-repudiation.

How do you create a digital signature:

Digital signature technology ensures the process of digitally signing documents is easy and secure. They provide a platform for sending and signing documents online and work with the appropriate Certificate Authorities to provide trusted digital certificates. The Certificate Authority you are using determines what kind of information you may be required to provide. There can also be set regulations and rules on to whom you send documents for signing and the way in which you send them. When you receive a document for signing via email, you must authenticate as per the Certificate Authority’s requirements and then proceed to sign the document by filling out an online form.

digital signatures work:

The mathematical algorithm generates a public key and a private key that is linked to each other. When a signer electronically signs a document, the mathematical algorithm generates data pertaining to the signed document by the signer, and the data is then encrypted. This data is also called a cryptographic hash. A hash function is a fixed-length string of numbers and letters generated from a mathematical algorithm. This generated string is unique to the file being hashed and is a one-way function, a computed hash cannot be reversed to find other files that may generate the same hash value. The signer has sole access to the private key and this private key is used to encrypt the document data. The encrypted information or encrypted hash is then transmitted and can be decrypted only by the signer’s public key. The receiver who receives the document also receives a copy of the signer’s public key which is used to decrypt the signature. A cryptographic hash is again generated on the receiver’s side. Both cryptographic hashes are checked to validate their authenticity. The document is considered genuine if they match.

Certificate Authority who are Trust Service Providers(TSP) provides digital certificates to ensure that the keys generated and documents signed are created in a secure environment.

Digital certificates help to validate the holder of a certificate. Digital certificates contain the public key of the sender and are digitally signed by a Certificate authority.

Public key infrastructure (PKI) includes regulations, protocols, rules, people, and systems that aid the distribution of public keys and the identity validation of users with digital certificates and a certificate authority.

Encryption with Digital Signature :

In many digital communications, it is desirable to exchange an encrypted messages than plaintext to achieve confidentiality. In public key encryption scheme, a public (encryption) key of sender is available in open domain, and hence anyone can spoof his identity and send any encrypted message to the receiver.

This makes it essential for users employing PKC for encryption to seek digital signatures along with encrypted data to be assured of message authentication and non-repudiation.

This can archived by combining digital signatures with encryption scheme. Let us briefly discuss how to achieve this requirement. There are two possibilities, sign-then-encrypt and encrypt-then-sign.

However, the crypto system based on sign-then-encrypt can be exploited by receiver to spoof identity of sender and sent that data to third party. Hence, this method is not preferred. The process of encrypt-then-sign is more reliable and widely adopted. This is depicted in the following illustration −

The receiver after receiving the encrypted data and signature on it, first verifies the signature using sender’s public key. After ensuring the validity of the signature, he then retrieves the data through decryption using his private key.

This is how a digital signature is sent:

· In the document platform or application, the sender chooses the file to be digitally signed.

· The sender’s computer calculates the file content’s unique hash value. The digital signature is created by encrypting this hash value with the sender’s private key.

· The receiver receives the original file as well as its digital signature.

· The receiver opens the associated document application, which recognizes the digitally signed file.

· The digital signature is then decrypted by the receiver’s computer using the sender’s public key.

· After that, the receiver’s computer computes the hash of the original file and compares it to the now-decrypted hash of the sender’s file.

Benefits of digital signatures

While digital signatures have caught the fancy of many corporates and executives, what exactly is it? Simply put, a digital signature is your electronic fingerprint. It lets you sign a document electronically and it validates the signer. It is a mathematical code that authenticates the document from the sender and ensures the document remains unaltered on reaching the recipient.

Fears about the security of digital signatures are reasonable, however, it uses an accepted format called a Public Key Infrastructure, which provides a very high level of security making it difficult to duplicate. Digital signatures make office paperwork far more efficient, but laws regarding this technology vary between countries. The benefits of digital signatures have more offices and companies getting on the bandwagon in favor of e-signatures, making for a far more efficient and secure workplace, digitally.

In many parts of the world including North America, the European Union, and APAC, digital signatures are legal and has the same value as hand signatures.

Advantages of digital signatures

· Saves time You no longer have to wait for your manager to return from a holiday or conference for that signature. Digital signatures ensure that businesses save on cost and time with documents and contracts signed off with a click of a button. There are huge savings in cost and time especially when the person required to sign is in a geographically different area. Documents can be signed off almost instantly, from anywhere. Be it a tablet, phone or computer, digital signatures can seamlessly ensure this otherwise tedious task is wrapped up in minutes.

· Cost savings Many companies also see significant cost savings, with little or no expense in ink, paper, printing, scanning, shipping/delivery, or travel expenses. There are also savings in other indirect costs such as filing, rekeying data, archiving, or tracking.

· Workflow efficiency With lesser delays, digital signatures ensure better efficiency in workflow. Managing and tracking documents are made easier, with lesser effort and time involved. Many features of digital signatures help speed up the work process. For instance, email notifications help remind the person to sign, while status tracking, help to know at which stage the document is at.

· Better customer experience Digital signatures provide the convenience of signing important documents where ever a customer or the person to sign is located. Salespersons do not have to wait for the customer to come to the bank or office. Documents can be signed off at the doorstep. This is ideal, especially in remote areas and smaller townships providing improved and personalized services. The customer has the freedom to be anywhere, and engage with a company, making services and businesses far more easy, quick, and user–friendly.

· Security When it comes to signatures, authenticity, and security are a priority. Digital signatures reduce the risk of duplication or alteration of the document itself. Digital signatures ensure that signatures are verified, authentic and legitimate. Signers are provided with PINs, passwords, and codes that can authenticate and verify their identity and approve their signatures. Time stamping provides the date and time of the signature and thus provides a track of the document, minimizing any risk of tampering or fraud. Security features embedded in digital signatures ensure that documents have not been altered without authorization.

· Legal validity Digital signatures provide authenticity and ensure that the signature is verified. This can stand in any court of law like any other signed paper document. Time stamping and the ability to track and easily archive documents improve and simplify audit and compliance.

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API

Application Programming Interface (API) is a software interface that allows two applications to interact with each other without any user intervention. API is a collection of software functions and procedures. In simple terms, API means a software code that can be accessed or executed. API is defined as a code that helps two different software’s to communicate and exchange data with each other.

It offers products or services to communicate with other products and services without having to know how they’re implemented.

API work?

To understand the functionality of the API, let see the following example:

API Example 1:

193Let see how API works using simple daily life example. Imagine that you went to a restaurant to take lunch or dinner. The waiter comes to you gives you a menu card, and you will provide personalize it order like you want a veg sandwich but without onion.

After some time, you will get your order from the waiter. However, it is not that simple as it looks as there is some process that happens in between.

Here, the waiter plays an important part as you will neither go to the kitchen to collect your order nor will you tell the kitchen staff what you want all this done by the waiter.

API also does the same by taking your request, and just like the waiter tell the system what you want and give a response back to you.

API Example 2:

After understanding the concept, let us take some more technical examples.

For example, you go to the movie site, you enter your movie, name, and credit card information, and behold, you print out tickets.

They are collaborating with other applications. This integration is called “seamless,” as you never have a clue when a software role is passed from one application to another.

Why would we need an API?

Here, are some reason for using API:

Application Programming Interface acronym API helps two different software’s to communicate and exchange data with each other.

It helps you to embed content from any site or application more efficiently.

APIs can access app components. The delivery of services and information is more flexible.

Content generated can be published automatically.

It allows the user or a company to customize the content and services which they use the most.

Software needs to change over time, and APIs help to anticipate changes.

Features of API

Here are some important features of API:

It offers a valuable service (data, function, audience,.).

It helps you to plan a business model.

Simple, flexible, quickly adopted.

Managed and measured.

Offers great developer support.

Types of API

There are mainly four main types of APIs:

Open APIs: These types of APIs are publicly available to use like OAuth APIs from Google. It has also not given any restriction to use them. So, they are also known as Public APIs.

Partner APIs: Specific rights or licenses to access this type of API because they are not available to the public.

Internal APIs: Internal or private. These APIs are developed by companies to use in their internal systems. It helps you to enhance the productivity of your teams.

Composite APIs: This type of API combines different data and service APIs.

Communication level of APIs:

Here, are some communication level of APIS:

High-Level APIs:

High-level APIs are those that we can generally use in REST form, where programmers have a high level of abstraction. These API’s mostly concerned about performing a limited functionality.

Low-Level APIs:

This kind of APIs has a lower level of abstraction, which means they are more detailed. It allows the programmer to manipulate functions within an application module or hardware at a granular level.

What is Web APIs?

A Web API is an application programming interface which is use either for web server or a web browser.

Two types of Web APIs are 1) Server-side API 2) Client-side API

1.Server-side:

Server-side web API is a programmatic interface that consist of one or more publicly exposed endpoints to a defined request–response message system. It is typically expressed in JSON or XML

2.Client-side:

A client-side web API is a programmatic interface helps to extend functionality within a web browser or other HTTP client.

Examples of web API:

Google Maps API’s allow developers to embed Google Maps on webpages by using a JavaScript or Flash interface.

YouTube API allows developers to integrate YouTube videos and functionality into websites or applications.

Twitter offers two APIs. The REST API helps developers to access Twitter data, and the search API provides methods for developers to interact with Twitter Search.

Amazon’s API gives developers access to Amazon’s product selection.

API Testing tools

Here are some popular API tools:

1) Postman

Postman is a plugin in Google Chrome, and it can be used for testing API services. It is a powerful HTTP client to check web services. For manual or exploratory testing, Postman is a good choice for testing API.

Features:

With Postman, almost all modern web API data can be extracted

Helps you to write Boolean tests within Postman Interface

You can create a collection of REST calls and save each call as part of a collection for execution in future

For transmitting and receiving REST information, Postman is more reliable.

2) Ping API

Ping-API is API testing allows us to write test script in JavaScript and CoffeeScript to test your APIs. It will enable inspecting the HTTP API call with a complete request and response data.

Features:

Ping- API to schedule test in every minutes or hour

Support for writing script to set request headers, body, and URL parameters. It supports for writing script to validate response headers and body

Validate CRUD flow and log in to Ping API

3) vREST

vREST API tool provides an online solution for automated testing, mocking, automatic recording, and specification of REST/HTTP APIs/RESTful APIs.

Features:

It provides an exhaustive tool to validate your REST APIs quickly

Helps you to delivers zero-defect web applications with less effort in API testing

You can validate your web application

No skilled resources are required, and it can generate documentation for your API specifications.

Application of API

Here, are important Applications of API (stands for Application Programming Interface):

Batch Distribution / Drive Traffic.

Expand Footprint.

Feature Development

Explore New Business Models.

Content Acquisition Advance Business Model.

Internal Content Distribution / Innovation.

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