What does block chain entail? And how secure is it?
Everyone with interests and assets in banking, investing, or cryptocurrency over the last 2 decades, may be familiar with the term “blockchain”, the record-keeping technology that governs the Bitcoin network.
What does Blockchain entail?
As most people find this technology so complex, why is it called blockchain? For starters, blockchain in all actuality is just a chain of blocks, but not in the literal sense of those words, but it applies to the context. When the words “block” and “chain” are taken in regards to this aspect, we are actually talking about the online digital information i.e. the “block” that is stored in a public database i.e. the “chain”.
Technically when a block stores new data it is added to the blockchain. As its name suggests, blockchain, consists of multiple blocks allotted together. For the following to occur, the block has to be added to the blockchain, however, four things must happen prior:
1. The transaction must occur along with your details.
2. That transaction must be verified by the servers.
3. That transaction must be stored into an allotted block.
4. The block must be given a hash code.
When the new block is added to the blockchain, it becomes publicly available for anyone to view, and that includes yourself. For e.g. if you were to view Bitcoin’s Blockchain, you would find that you have access to everyone's transaction data, along with information about When? i.e. “time”, Where? i.e. “height”, and by Who? i.e. “relayed by” the block was allotted to the blockchain.
Is Privacy a Concern in Blockchain?
Honestly, anyone has the privilege to view the contents of the blockchain, as it is public and managed by a decentralized consensus, but any individual can choose to establish a connection tolook  their computers to the blockchain network as an additional node. By doing so, their registered computer is able to receive a copy of the blockchain that sends regular updates automatically whenever an additional  block is added to the blockchain.
And as you are looking over the bitcoin blockchain, you will observe that you do not have the authorization nor the access to identify the personal information about the users making their transactions. Transactions on the blockchain may not be completely anonymous, although personal information about the user is limited to their username or digital signature.
Another important question is raised due to the following aspect; if one doesn't know who has added blocks to the blockchain, how can we trust the blockchain or the network of decentralized computers responsible with its upkeep?
Blockchain, Security and Concerns about getting Hacked:
As most technologies do, blockchain technology is held accountable for the issues of security and upholding its users trust in several ways. Firstly, brand new blocks by default are stored in a linear and chronological order. Additional blocks are always added to the end of the blockchain. If we take a look at the bitcoin blockchain, we'll see that every block has a position on the chain, called a “height.” In a recent survey conducted in the month of January of the year 2020, the block’s height in the blockchain had topped 615,400 blocks.
And this is the reason it is important to security regarding the users and transactions. Let's take an example of Amazon.Inc. Suppose, a hacker attempts to edit or fidget with your transaction from Amazon so that you will then have to pay for your purchase twice. The moment when they edit the monetary amount of your transaction, the block’s hash code will change to another unique hash code. The other block in the chain will still contain the original hash code, and the hacker would then need to update that block as well in order to cover their crimes and actions. However, in doing so, the hacker would change that block’s hash code. And then the next, and so on, and so forth.
So basically in order to make changes to a single block of transaction, a hacker would need to make changes in every block after it on the blockchain. To recalculate all those hash codes, it would take an enormous and unconventional amount of computing power. In simpler words, once a block has been added to the blockchain, it becomes extremely tedious to edit its contents and impossible to erase.
To ensure additional security, the most common example employed by bitcoin blockchain is called “Proof of Work”. Technically in the "Proof of Work" system, the users computers must “prove” that they have done “work” by solving complex computational math problems.  Although "Proof of Work" does not make attacks by the hacker impossible, it does make them moderately useless. Consider, a hacker who wants to coordinate an attack on the blockchain, they would need to firstly control more than 50% of all computing power existing on the blockchain, so they are able to overwhelm all other the other participants in the network. Due to the tremendous size of the bitcoin blockchain, a proper 51% attack is most certainly not worth the resources and efforts applied, and more than likely impossible to execute.
Practical Applications of a Blockchain:
The blocks on the blockchain, store data about monetary transactions but, in reality the blockchain is actually a reliable source for storing data about multiple types of transactions, as well. As a matter of fact, the blockchain technology can be used to store information about property, a stop in the supply chain, and even during elections regarding votes a candidate receives.
The following are the applications of blockchain in the industry:
1. Banks can make use of the blockchain for their transactions.
2. Useful for cryptocurrency.
3. Healthcare Industry for managing data.
4. Property Records for the government and personal use.
5. Voting for a designated candidate.
Blockchain:- Efficiency and Limits:
Even though it is somewhat complex, the blockchain’s potential as a decentralized form of record keeping is beyond comparison. It offers  great privacy for it's users and powerful security measures to lower processing fees and run into fewer errors. In addition to this, blockchain technology might see applications beyond those outlined above. Only the coming years will tell.
1. Human involvement is eliminated entirely by increased accuracy in verification processes.
2. By removing third-party verification, costs can be reduced.
3. Decentralization makes it extremely difficult for anyone to tamper with its data.
4. Transactions are provided with security, privacy and efficiency.
5. Blockchain is a transparent technology.
1. Significant technological costs due to mining of bitcoins.
2. Lower transactions conducted every second.
3. Blockchain has a history of use in illegal activities.
4. Although considered impossible, there's a chance that it can be hacked.
The Future of Blockchain:
As many practical applications for the technology have already been implemented and explored, the blockchain is finally making a name for itself, and that is recently because of bitcoins and cryptocurrency. As a rapidly growing form of transaction and storage network, and on the mind of every investor globally, the blockchain stands to make business, organizational and government operations, conducted with better accuracy, efficiency and security.
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