What on earth is a Blockchain?

What on earth is a Blockchain?

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Arpan Pandey
·Dec 11, 2021·

2 min read

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Table of contents

  • Introduction
  • What is a block?
  • What is a hash?
  • The Genesis Block
  • The Chain
  • Concluding


With all the hype regarding cryptocurrencies and blockchain, it is quite easy to feel left out. So, let's embark on a journey through the fundamentals. We will start with what Wikipedia gives us, shall we?

A blockchain is continuously growing list of records called blocks, which are linked and secured using cryptography.

What is a block?

Well, you can think of a block as a container of sorts. It has some basic data later:

  • Data- The actual data that contains all the individual transactions and stuff like a ledger.
  • Previous Hash- This is the hash of the previous block. It is used to link the blocks together.
  • Hash- This is the hash of the current block and is computed based on all of the data in the block.
  • Some other stuff...

What is a hash?

You must've noticed that I use this term hash quite a lot. So, let's find out what a hash is. A hash in its most basic form is just a value that is calculated based on the data. It is unique for any data given and has many other characteristics that deserves its own post. But, until I make one you can visit my old post over here.

The Genesis Block

20211211_202627_0000.png The Genesis Block is where it all begins. It is the first block in a blockchain. It is created when the blockchain is created. It has no previous hash since it is the very first block.

The Chain

20211211_203926_0000.png The hash value of the genesis block is used as the previous hash value by the second block in the chain, which is then used by the third block and so on. This creates a sort of chain between the blocks. And if any bad actor tries to interfere with a block it will change the hash of the block which will cause the whole chain to be invalid from that point on.


This was a very very basic introduction to the world of blockchain and hopefully we now have a stage set for a series on Blockchain.

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