SHA-2 Family リファレンス
リファレンス 用 the SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, および SHA-512/256 ハッシュ 関数.
Family Overview
The SHA-2 family comprises six hash functions defined in FIPS 180-4 with output sizes from 224 to 512 bits. SHA-256 and SHA-512 are the base functions; the others are truncated or reparameterized variants. All use Merkle-Damgard construction with different word sizes and round counts. SHA-256 operates on 32-bit words with 64 rounds, while SHA-512 uses 64-bit words with 80 rounds.
- SHA-256
- 32-bit words, 64 rounds
- SHA-512
- 64-bit words, 80 rounds
- SHA-224/384
- Truncated variants
32-byte output64-byte outputdifferent IVsSecurity and Performance
No practical collision or preimage attacks are known on any SHA-2 variant. The best theoretical attacks reach about 46 of 64 rounds for SHA-256 collisions. SHA-512/256 offers better performance on 64-bit platforms than SHA-256 while providing equivalent security. The family is universally deployed in TLS, SSH, code signing, and blockchain protocols. Hardware acceleration is available on modern x86 and ARM processors.
- collisions
- No practical attack
- performance
- HW accelerated
- deployment
- Universal in protocols
theoretical 46 roundsSHA-NI, ARMv8 cryptoTLS, SSH, signing