What is blockchain ?
Blockchain is a decentralized ledger tracking digital assets on Peer to Peer Network. Digital assets can be Bank accounts, GST input/output, Sales and Purchase books, Account ledgers etc.
Let’s assumes a book, each page in a book references to the previous page.Book is a Blockchain where page is a block and entry in page is a recorded transaction. It’s secure because it is easy to detect if a block has been removed or altered and it is easy to validate book since the pages or blocks are built on top of each other hence it is impossible to temper impervious entry in the book without other noticing it.
Blockchain Simplified
Each block in blockchain is built on top of the recent block and use its previous block’s signature and Nonce i.e. random string.Building a block and adding it in the blockchain is the task of miners and committer/endorsers in case of Ether-um and Hyperlegder respectively.In case of public blockchain, it is made computational difficult to add a block to prevent attack.
Etherum : Miners guess a number (Nonce) in such a way that if it gets signature less than the most recent block’s signature added in the blockchain. This process of guessing a number to get signature less than the signature of previous block is called POW i.e Proof of Work.
Hyperledger : In case of Private blockchain Network administrator can choose other methods i.e PFBT, POS etc. to add a block as they can trust the nodes using a smart contract.
Conclusion
It’s a decentralized database which stores information in the form of transactions.
It can be public or private.
Immutable.
Cryptographic-ally highly secure.
Transactions gets recorded via consensus algorithms.
