#binary tutorial

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Contents

Python:

Introduction to Variables

User Input and Selection

An Introduction to While Loops

Putting it Together

Introduction to Lists

Website:

Into to HTML

Binary:

Decimal to Binary and Vice Versa

Basic Logic Gates

Hacking:

Securing Kali Against Hacking

Finding Open Ports With Nmap

Finding Exploits

Hacking Metasploitable

Staying Safe Online:

Spotting Phishing Attacks

HTTP vs HTTPS

Good Password Etiquette

Proxies and VPNs

MultiFactor Authentication

Virtual Machines:

Kali for VMWare

Kali for VirtualBox

Creating a Live USB

Linux:

Directory Traversal and File Creation/Deletion

Basic Networking Commands

Remote Access

Finding Files

Blue Team:

Static Malware Analysis 101

General Programming:

Data types

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Binary Pt. 2: Logic Gates and Truth Tables

A bit in binary is boolean, meaning it is either true or false, but by using logic gates you can make decisions and calculations.

Truth tables are a way to demonstrate the logic that you have planned out with logic gates by showing all possible combinations of inputs and outputs. As this is the first part of the guide on boolean logic, I’m only going to focus on the three most basic logic gates and their truth tables.

AND Gate:

This is the symbol for an AND gate. Q is 1 when both A and B are 1. Otherwise Q is 0. We can show this on a truth table like so:

Columns A and B show the two inputs to the gate, while column Q shows the output as a result.

OR Gate:

An OR gate equals 1 when A or B are 1. This also includes if both A and B are true.

NOT Gate:

NOT gates are the simplest logic gates: they simply reverse what is entered. NOT gates are different to AND/OR gates because they only have one input. This also makes the truth table simpler.

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Binary pt. 1: Converting Decimal to Binary and Vice Versa

Decimal to Binary:

Binary seems intimidating, I know. It’s just so different to what we’re used to. Luckily though it’s not actually that hard, so in this tutorial I will teach you how to convert decimal to binary, and my next guide will be the other way around

The first thing to know is that a single binary digit is called a “bit”, and they are normally grouped in eights, called “bytes”. An example of a byte is “01000101“. There are 256 combinations of bits from one byte, so the biggest number that can be stored is 255 (one of the combinations is zero).

Let’s move on to how to convert a number from decimal to binary. I’m going to get a random number from google that we can work out together.

176, thank you google.

I start by writing out what each bit is worth if it is 1 as headings in a table. Counting from the right, each bit is worth double the last one, counting from 1. This gives me the following table:

Now we start reading from the left. If the heading we are on can be subtracted from the number we are trying to convert and give a result above 0, we put a one in that heading, otherwise we put a 0.

That is very wordy so I’ll show you instead. 176 - 128 = 48, so we put a 1 there:

After the last calculation we are left with 48. 48 - 64 = -16, so we put a 0 in that column.

We still have 48. 48 - 32 = 16.

16 - 16 = 0, so we put a 1. We are left with nothing, so we know the rest of the bits are going to be 0.

Our byte is 10110000.

And Vice Versa:

So know you know how to convert to binary, but how do you convert from binary to decimal? The short answer is you do the opposite.

For this we’re going to use the same byte we just worked out (10110000). Write out our byte, then write the headings on top.

Now we add all of the headings of ‘on’ bits together. We work out 128 + 32 + 16 which gives us an answer of 176.

Practice:

I cannot stress enough how useful practice is for learning this, so here are some practice questions. Once you’ve finished you can look up the answers online to check.

129 to binary

10100010 to decimal

255 to binary

254 to binary

00100011 to decimal

If you have any questions feel free to contact me and ask and I’ll help as much as I can.