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.Dd October 14, 2015 .Dt SHA3 3 .Os .Sh NAME .Nm SHA3 .Nd NIST FIPS PUB 202: SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions .Sh SYNOPSIS n sha3.h .Ft void .Fn SHA3_224_Init "SHA3_224_CTX *ctx" .Ft void .Fn SHA3_224_Update "SHA3_224_CTX *ctx" "const uint8_t *buf" "size_t len" .Ft void .Fn SHA3_224_Final "uint8_t digest[SHA3_224_DIGEST_LENGTH]" "SHA3_224_CTX *ctx" .Ft void .Fn SHA3_256_Init "SHA3_256_CTX *ctx" .Ft void .Fn SHA3_256_Update "SHA3_256_CTX *ctx" "const uint8_t *buf" "size_t len" .Ft void .Fn SHA3_256_Final "uint8_t digest[SHA3_256_DIGEST_LENGTH]" "SHA3_256_CTX *ctx" .Ft void .Fn SHA3_384_Init "SHA3_384_CTX *ctx" .Ft void .Fn SHA3_384_Update "SHA3_384_CTX *ctx" "const uint8_t *buf" "size_t len" .Ft void .Fn SHA3_384_Final "uint8_t digest[SHA3_384_DIGEST_LENGTH]" "SHA3_384_CTX *ctx" .Ft void .Fn SHA3_512_Init "SHA3_512_CTX *ctx" .Ft void .Fn SHA3_512_Update "SHA3_512_CTX *ctx" "const uint8_t *buf" "size_t len" .Ft void .Fn SHA3_512_Final "uint8_t digest[SHA3_512_DIGEST_LENGTH]" "SHA3_512_CTX *ctx" .Sh DESCRIPTION The .Nm functions implement the cryptographic hash functions of the NIST SHA-3 standard, FIPS PUB 202. The .Nm functions compress an arbitrary-length message m into short fixed-length octet strings SHA3-224(m), SHA3-256(m), etc., called a cryptographic digest or hash.
p Before using the .Nm functions, applications should first call .Xr SHA3_Selftest 3 and confirm that it succeeded.
p Only the .Nm SHA3_256 functions are specified in detail; the .Nm SHA3_224 , .Nm SHA3_384 , and .Nm SHA3_512 functions are exactly analogous.
p The caller must allocate memory for a .Vt SHA3_256_CTX object to hold the state of a SHA3-256 hash computation over a message. .Vt SHA3_256_CTX objects are slightly over 200 bytes, and may be copied or relocated in memory. l -tag -width abcd t Fn SHA3_256_Init "ctx" Initialize a SHA3-256 context. Must be done before any other operations on .Fa ctx . t Fn SHA3_256_Update "ctx" "data" "len" Append .Fa len octets at .Fa data to the message. t Fn SHA3_256_Final "digest" "ctx" Store at .Fa digest the 32-octet SHA3-256 hash of the message obtained by concatenating all prior inputs to .Fn SHA3_256_Update on .Fa ctx .
p Subsequent use of .Fa ctx is not allowed, unless it is reinitialized with .Fn SHA3_256_Init . .El .Sh SEE ALSO .Xr keccak 3 , .Xr SHA3_Selftest 3 , .Xr SHAKE 3 .Sh STANDARDS .Rs .%A National Institute of Standards and Technology .%T SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions .%O FIPS PUB 202 .%D August 2015 .Re .Sh AUTHORS .An Taylor R Campbell Aq campbell+sha3@mumble.net