Hash

A hash is a fixed-length alphanumeric string generated by a cryptographic hash function, which transforms input data of any size into a unique and consistent output. In the context of Bitcoin, hashes are essential for identifying blocks, transactions, and other data within the blockchain. Each hash acts as a digital fingerprint, ensuring that the data it represents remains unaltered.

In Bitcoin, the hash of a block serves as its unique identifier and is critical in linking blocks together to form the blockchain. This linkage creates a tamper-evident structure, where altering any block would change its hash, thereby breaking the chain. The use of hashes ensures the integrity and immutability of the network by making it computationally infeasible to modify past records without detection. Because of these properties, hashes play a foundational role in securing the Bitcoin blockchain and enabling trustless transactions.