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SHAKE

Section: C Library Functions (3)
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BSD mandoc

NAME

SHAKE - NIST FIPS PUB 202: SH-3 Standard: Permutatio-Based Hash and Extendabl-Output Functions

LIBRARY

Lb libmd

SYNOPSIS

In sha3.h Ft void Fn SHAKE128_Init SHAKE128_CTX *ctx Ft void Fn SHAKE128_Update SHAKE128_CTX *ctx const uint8_t *buf size_t len Ft void Fn SHAKE128_Final uint8_t *output[] size_t outlen SHAKE128_CTX *ctx Ft void Fn SHAKE256_Init SHAKE256_CTX *ctx Ft void Fn SHAKE256_Update SHAKE256_CTX *ctx const uint8_t *buf size_t len Ft void Fn SHAKE256_Final uint8_t *output[] size_t outlen SHAKE256_CTX *ctx

DESCRIPTION

The functions implement the extendabl-output functions of the NIST SH-3 standard, FIPS PUB 202. The functions absorb an arbitrar-length message m and yield an arbitrar-length output SHAKE128(m) or SHAKE256(m), truncated to a specified number of octets.

Before using the functions, applications should first call SHA3_Selftest3 and confirm that it succeeded.

Only the SHAKE128 functions are specified in detail; the SHAKE256 functions are analogous.

The caller must allocate memory for a Vt SHAKE128_CTX object to hold the state of a SHAKE128 computation over a message. Vt SHAKE128_CTX objects may be copied or relocated in memory.

Fn SHAKE128_Init ctx: Initialize a SHAKE128 context. Must be done before any other operations on Fa ctx .
Fn SHAKE128_Update ctx data len: Append Fa len octets at Fa data to the message.
Fn SHAKE128_Final output outlen ctx: Store at Fa output the first Fa outlen octets of the SHAKE128 output for the message obtained by concatenating all prior inputs to Fn SHAKE128_Update on Fa ctx .
Subsequent use of Fa ctx is not allowed, unless it is reinitialized with Fn SHAKE128_Init .

STANDARDS

: National Institute of Standards and Technology SH-3 Standard: Permutatio-Based Hash and Extendabl-Output Functions FIPS PUB 202 August 2015

AUTHORS

An Taylor R Campbell Aq campbell+sha3@mumble.net