Glossary
Cryptographic Hash Function
A one-way function that maps any input to a fixed-size digest, used everywhere on a blockchain to link blocks, derive addresses, and commit to data.
A cryptographic hash function turns any input — a transaction, a file, a block header — into a fixed-length digest that is easy to compute but practically impossible to invert. Tiny changes to the input produce wildly different digests (the "avalanche" property), and finding two inputs with the same digest (a collision) is infeasible.
Blockchains lean on these properties at every level: block headers chain via their previous-hash field, transactions commit to data via their hash, and addresses are themselves hashes of public keys.