Cryptography
SHA-256
Also known as: SHA-2 (256-bit), FIPS 180-4 SHA-256
Definition
A 256-bit cryptographic hash function from the SHA-2 family, widely used for digital signatures, TLS, blockchains, and integrity verification.
Examples
- Bitcoin uses double SHA-256 for block hashing and proof-of-work.
- Modern X.509 certificates are signed with SHA-256 (signature algorithm sha256WithRSAEncryption).
Related terms
Cryptographic Hash Function
A deterministic one-way function that maps arbitrary-length input to a fixed-length digest, designed to be collision-, preimage-, and second-preimage-resistant.
SHA-1
A cryptographic hash function producing a 160-bit digest, designed by the NSA in 1995 and now considered broken for collision resistance.
SHA-3
A family of hash functions based on the Keccak sponge construction, standardized by NIST as a structurally different alternative to SHA-2.
HMAC
A keyed Message Authentication Code construction built on top of a cryptographic hash function, defined in RFC 2104 and FIPS 198-1.
Digital Signature
A public-key cryptographic mechanism that proves the authenticity, integrity and non-repudiation of a message or document.
BLAKE2
A fast, modern cryptographic hash function specified in RFC 7693, offering security comparable to SHA-3 with significantly higher performance in software.