After discussing all the basic components of Blockchain, it’s time to

give a definition to Blockchain.

Blockchain is a distributed ledger with a decentralized consensus

where the participant nodes can send the transaction requests to

the ledger that can be added and replicated to the other nodes in

near real time. The data in a Blockchain is immutable or can be

added in the append-only mode; hence, it’s transparent and

cryptographically secure.

1.6 How Bitcoin Blockchain Works

The description of Blockchain that we just covered is as per the

original concept of the technology as introduced by Satoshi in

Bitcoin. Let’s now explore how the data is added to such a

Blockchain ledger. The Blockchain transactions are linked to each

other in a unique data structure known as the Merkle tree. As shown

in Figure 1.7, the hash of each transaction is calculated and paired

with the hash of the next transaction. Now, the collective hash of

these two hashes is again paired with another collective hash. This

process is repeated till we reach the root hash, which is also known

as the Merkle root that gets saved to the Block header. Refer to

Figure 1.7 as follows: