A hash is the output of a hash function, a function which is a mathematically reproducible but irreversible process that takes in an arbitrary length input and produces a fixed length output. The same input will always result in the same output. Hashing is central to Bitcoin mining as well as the generation of Bitcoin addresses.
A hash is the output of a hash function, a function which is a mathematically reproducible but irreversible process that takes in an arbitrary length input and produces a fixed length output. The same input will always result in the same output. Hash functions often create output which is random looking, and secure hash functions cannot be reversed, i.e. the input cannot be known just by having the hash, and two inputs are unlikely to result in the same output.
Hashing is central to Bitcoin mining as part of the Proof of Work. In Bitcoin, the hash function used for the PoW is SHA256 double. Hashes are also used in Bitcoin addresses and as unique identifiers for blocks and transactions.
