Why is "Blockchain" called a blockchain?

A very fundamental question before diving deep into more complex topics. What makes blockchain, a "Blockchain"?

Let’s break the keyword into 2 parts: Block and Chain

What is a Block?

A block is a representation of group of related records. It has 2 parts - a data field that represent these records and metadata (data about data) that describe the block.

Let’s assume you are recording few transactions in a ledger or notebook. Each page in the ledger can be considered a block and the transactions within it represent the block data.

Here’s a simple representation of a block, in the context of blockchain. (Credit - https://andersbrownworth.com/blockchain)

• Block ID - Human readable unique identifier of a block

• Nonce - A complex number that has to be rightly guessed by a miner, before a block can be successfully added to the blockchain

• Data - Any functional data or group of records, usually encrypted

• Hash - Machine readable representation of data in the block, that is unique to the data. Any change in data will result in a different hash

What is a Chain?

When the blocks are connected to each other, we end up with a chain of blocks. And thus we have a blockchain.

But how do you connect these blocks?

Pay special attention to the highlighted fields, “Hash” and “Prev”.

Value in the “Prev” field of Block #2 has the same value as “Hash” field of Block #1. So these blocks come after one another in a blockchain.

By extending this to thousands and millions of blocks, we end up in a massive entity common known as Blockchain.

So how do you explain Blockchain to your friend?

A blockchain is a massive distributed ledger containing blocks, which are nothing but a group of records, that are chained together using hashes. Any change to block data will modify the hash and thus break the chain

This distributed ledger is not stored in a single place, but spread across computers (referred as nodes) around the world.

In subsequent posts, I will cover certain important concepts around cryptography that makes the blockchain secure and immutable.

I strongly recommend you to play around with blockchains in this awesome demo website - https://andersbrownworth.com/blockchain/blockchain

Goodbye until next time and keep rocking!