A blockchain is a shared public ledger that serves as a digital "register of transactions" in which transactions are recorded as records. This enables the Bitcoin network to "keep a perpetual record of all transactions made," using a distributed consensus of hundreds of thousands of networked computers. Each such computer keeps a copy of the blockchain, and any of them can be chosen as a temporary "validator," validating newly generated blocks and eventually becoming "miners" that earn a reward by helping to validate the latest transactions.
A blockchain is a database, and the data within it represents
a record of all the transactions (also called "transactions") that have
been processed by all the computers connected to the network.
Bitcoin uses a so-called proof-of-work scheme to authenticate
transactions, while securing the network against double-spending
attacks. The main objective of Bitcoin is to provide a secure,
decentralized payment system with minimal transaction fees.
The transaction-processing records themselves are verified using
cryptography, making a double spend impossible. They are also validated
by any miner that receives them, ensuring that they are received by the
"correct" computer.
Curel–Smith diagram of blockchain
A blockchain is essentially a sequence of blocks or other entities that are linked in a chain. While it is possible to create a blockchain without blocks at all, it is more common to use a "blockchain schema": one or more entities (chains in a database) and the rules on how they are related to each other.
Bitcoin network
The network, sometimes called the peer-to-peer network, is the collection of nodes that participate in bitcoin's distributed network: the combination of software, network, and community participation that drives the operation of bitcoin. In 2014, the network was estimated to be 3.5 million nodes—that is, computers connected to the Internet and mining bitcoin.[85] It is composed of individual computers secured in so-called "mining pools" that do not split bitcoins obtained in any transaction. Mining is the process by which new bitcoin are released to the public ledger of transactions.
The size of mining pools, represented by the share of computing power from individual computers in the pool, has grown to account for more than 60% of computing power on the Bitcoin network. A mining pool includes the total computing power of its constituent members. Mining is rewarded by new bitcoin