SHA-256
A 256-bit cryptographic hash function used for transaction IDs, Merkle trees, and proof of work.
SHA-256 is a member of the SHA-2 family of cryptographic hash functions. It takes input data of any size and deterministically produces a 256-bit output, while making it computationally infeasible to recover the input or find two useful inputs with the same hash.
Bitcoin and Bitcoin Cash use double SHA-256 in proof-of-work mining and transaction identifiers. Miners repeatedly hash block headers with different nonces until the resulting value is below the current difficulty target.
SHA-256 is a hash function, not encryption: it does not hide data in a reversible way. Its key properties for blockchains are determinism, preimage resistance, collision resistance, and the avalanche effect.
Related terms
4 linkedExplore connected entries beyond the alphabetical index.
Proof of Work (PoW)
→A consensus algorithm where computing power is used to solve complex problems, verify transactions, and create new blocks.
Mining
→The process by which new coins or tokens are minted and transactions are confirmed on a blockchain through computational work.
Mining Difficulty
→Mining difficulty measures how hard it is to find a valid proof-of-work block and adjusts to keep average block times near target.
Merkle tree
→A Merkle tree is a binary tree of hashes that enables efficient verification of large data sets, used in blockchains for transaction inclusion proofs.
All terms and definitions may update as the Cryptionary improves.
