blockchain

Blockchain

Blockchain is a distributed ledger technology, not a person. It records and verifies transactions across a network of computers in a way that makes retroactive alteration extremely difficult. The ledger is organized into a chain of blocks, each containing a list of transactions and a cryptographic link to the previous block, typically via a hash.

Key characteristics:

• Decentralization: no single central authority maintains the entire ledger.
• Immutability: once data is recorded and confirmed, altering it is computationally hard.
• Transparency: participants can verify transactions, though privacy mechanisms may be employed.
• Consensus: network nodes agree on the current state of the ledger through protocols such as proof of work or proof of stake.

Origins and usage:

• The concept evolved from earlier work on cryptographic chains and timestamping, and was popularized by the advent of Bitcoin in 2009, where the blockchain underpins the cryptocurrency’s transaction history.
• Beyond currencies, blockchains are used to record various types of asset transfers, supply chain events, smart contracts, and decentralized applications.