BLOCKCHAIN – A discovery that changed the world

“Man is a curious being by nature. To quench his thirst of knowledge he finds solution to the existing problems.”

In 1991 a secure chain of blocks was first described by Stuart Haber and W Scott Stornetta. Then in the year 2008 developers working under the pseudonym “Satoshi Nakamoto” released a white paper which established the model for the blockchain network.

Blockchain is one such technology which has proved to be a cure!

Blockchain, also known as Distributed Ledger Technology, with the use of decentralization and cryptographic hashing makes the history of any digital asset immutable and pellucid.

What does decentralization mean?

In a decentralized blockchain network each member in the network has a copy of the exact same data in the form of a distributed ledger. If a member's ledger is bastardized or modified then it will be rejected by most of the members in the network.

The data is not centralised instead is distributed and is independent at each location.

What does cryptographic hashing mean?

Cryptographic hashing helps the system to maintain security.A cryptographic hash function combines the message-passing capabilities of hash functions with security properties. Cryptographic hash function has many applications which includes digital signature, uniquely identifying files and detecting duplicate data.

Blockchain in simple terms is a way to track the movement of value from point X to point Y without involving a third party to check.

Blockchain is known as blockchain since its all the transactions are settled in clusters called block. A block consists of 3 parts:

1) Hash of block

2) Data

3) Hash of previous block

A hash function is responsible to turn an input into a string of bytes with a fixed length and structure. This value which is created is called a hash value.

How does one detect whether someone is trying to hack the system or not?

From the above figure we can see that there is a chain of 3 blocks and each block has a hash value and the value of the hash of previous block. We can see that the 3rd block is pointing towards second block since the hash value of second block is stored in 3rd and the hash value of 1st block is stored in second block. Now if we make a change in the second block its hash value will be changed and the further blocks will be invalid because it will be holding wrong previous hash values. Blockchain somewhat is similar to a linked list (it consists of nodes where each node has a data field and a reference link to the previous node of the list). The first block is called a genesis block, since there is no block before it, the previous hash value is represented as 0000.

For every block formed, each hash is calculated. A hash apes the fingerprint of a person because its idiosyncratic. For every change in the block the hash value gets changed. Thus, we can detect change in the block. If someone tampers with the second block then the hash code of it will change and won’t match the third block’s previous hash code.

“This is why a small change also can be detected because the hash value will be changed.”

Consider a farmer agreed to work on the land of someone from 2020 to 2030. Suppose the owner changes the value to 2040 the farmer will be in huge loss. Now if this data is stored in a blockchain then if the owner tries to tamper with the data we will easily get to know!!

Below is the code to represent a block:

Class block {

constructor (index, previoushash, Timestamp, Data,hash){






Applications of blockchain:

There are many applications of blockchain and one such application is “supply chain management”.

Consider a place called “Ohio town” where a large number of chickens is infected with some particular disease. Thus, to avoid selling bad products from a farm we need to track and trace the path. Because if we do not trace then it will create a huge havoc. This is where blockchain proved to be a boon.

” Nestle has tried to implement this technology on a large scale for the baby food to avoid selling bad milk products”

Blockchain: Boon or Bane

Blockchain requires a lot of computing power which ultimately results in the consumption of huge amount of electricity and cooling power.

We all need to ponder upon one question!!

The greatest advantage of blockchain is being unbreakable, permanent and being anonymous. We don’t know the identity of the one who is having the key. If a criminal record is being added in the blockchain and that criminal is found not guilty, still his history will forever be stored and will follow the person hence blockchain its immutable. Is it really a boon?

What personally I conclude is that blockchain’s greatest advantage can prove to be a disadvantage! Like everything in the world, it also has consequences. We need to realise its risk and use it in a proper manner.

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