Since v 2.07 See also Comparison of cryptographic hash functions Comparison of cryptography libraries Hash function security summary Hashcash HMAC International Association for Cryptologic Research (IACR) sha1sum (sha224sum, sha256sum, sha384sum and sha512sum) commands Trusted timestamping References Further reading Henri Gilbert, Helena Handschuh: Security Analysis of SHA-256 and Sisters. Selected Areas in Cryptography 2003: pp175–193 External links Descriptions of SHA-256, SHA-384, and SHA-512 from NIST SHA-2 Checker – SHAChecker to check one's SSL compatibility for SHA-2 SHA-256 Calculator – SHA-256 Calculator SHA-256 Hash Generator – SHA256 Generator - Also serves other critical secure hash algorithms Specifications for a Secure Hash Standard (SHS) – Draft for proposed SHS (SHA-0) Secure Hash Standard (SHS) – Proposed SHS (SHA-0) CSRC Cryptographic Toolkit – Official NIST site for the Secure Hash Standard FIPS PUB 180-4: Secure Hash Standard (SHS) (PDF, 834 KB) – Current version of the Secure Hash Standard (SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512), August 2015 Test vectors for SHA-256/384/512 from the NESSIE project Test vectors for SHA-1, SHA-2 from NIST site NIST Cryptographic Hash Project – SHA-3 competition : "A 224-bit One-way Hash Function: SHA-224" : "US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)"; contains sample C implementation SHA-256 algorithm demonstration Cryptographic hash functions Articles with example pseudocode Checksum algorithms National Security Agency cryptography