Blockchain

July 3, 2021, 9:56 a.m.

Blockchain is a decentralized system of secured and trusted distributed databases which records and shares the transaction details across many nodes. So, that the data is not modified.
"Structures that stores transactional records, also known as block, of the public in several databases, known as the chain in a network connected through peer to peer nodes."

So each and every transaction which happens on a blockchain netowrk is distributed across all the nodes on the blockchain each and every participant has the same copy of ledger and it's immutable ledger once a records ot a transaction is registered it cannot be modified.

In a blockchain, each block linked to its previous block, the transaction become invalid for a specific bitcoin which has already been spent.

A block contains Data, Nonce, Hash & Previous Hash.

Data: Sender's address, Receiver's address & Transaction amount.

Nonce: Random value used to vary the output of the hash.

Previous Hash: Hash value of previous block.

Hash: Hash is like a digital fingerprint its the fingerprint of current block.

Features: 

1) Distributed ledger shared among all the users.

2) Highly secured

3) Automation capability.

Mining:

In a blockchain, when miners use their resource (time, money, electricity etc.) to validate new transaction and record them on public ledger, they are given reward.