Data
A transaction is an exchange of bitcoin for other currencies or other bitcoin. When two parties exchange bitcoin, both receive one bitcoin.
Each transaction that is broadcast to the network is added to a block. The block's transactions are aggregated and hashed to create a hash. This is called a Merkle root. The block also includes a hash of the preceding block. Every block starts with this data.
At intervals, the network elects a group of about a dozen Bitcoin miners, or nodes, who authenticate and append new blocks to the blockchain. The newest block is hashed to create a hash, and a Merkle tree is built to link that hash to all the hashes in the block.[citation needed]
Blocks are chained one after the other to create a chain of blocks. A block at the beginning of the chain is called the genesis block. No block may reference a previous block as all blocks are linked together with a hash of the previous block's hash.[citation needed] The first block in the chain is also known as the genesis block or the mother block. The numbers of transactions in each block are accumulated to show the usage of the digital currency. In order to maintain the security of the system, Bitcoin Core only accepts the longest valid chain, which : “...is the longest blockchain that complies with common sense.”
Blocks are produced at approximately every ten minutes. Transactions are registered to a blockchain when they are received.
Blocks and transactions are stored in a distributed digital ledger called the blockchain. They are validated by cryptographic hash function. This guarantees the integrity of the data stored in the blockchain. It also allows Bitcoin nodes to make a "first-seen" validation, ensuring they see the transactions and blocks first, and validate them according to their own rules.
The current chain of blocks is validated every few hours.
The ledger represents an open, distributed database with no centralized party or management. This feature is critical, as the blockchain is the only way to record transactions in a way that is decentralized, cannot be altered, and cannot be compromised. All nodes interact in a consensus process that provides atomic transactions.
Data structure
Every full bitcoin block contains a header, a list of transactions, and a merkle root. The merkle root proof is a cryptographic hash of the block header, which contains several pieces of information, such as the timestamp, hash of the previous block