SHAKE(3)                   Library Functions Manual                   SHAKE(3)

NAME
     SHAKE - NIST FIPS PUB 202: SHA-3 Standard: Permutation-Based Hash and
     Extendable-Output Functions

LIBRARY
     Message Digest (MD4, MD5, etc.) Support Library (libmd, -lmd)

SYNOPSIS
     #include <sha3.h>

     void
     SHAKE128_Init(SHAKE128_CTX *ctx);

     void
     SHAKE128_Update(SHAKE128_CTX *ctx, const uint8_t *buf, size_t len);

     void
     SHAKE128_Final(uint8_t *output[], size_t outlen, SHAKE128_CTX *ctx);

     void
     SHAKE256_Init(SHAKE256_CTX *ctx);

     void
     SHAKE256_Update(SHAKE256_CTX *ctx, const uint8_t *buf, size_t len);

     void
     SHAKE256_Final(uint8_t *output[], size_t outlen, SHAKE256_CTX *ctx);

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

     Before using the SHAKE functions, applications should first call
     SHA3_Selftest(3) 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 SHAKE128_CTX object to hold the
     state of a SHAKE128 computation over a message.  SHAKE128_CTX objects may
     be copied or relocated in memory.

     SHAKE128_Init(ctx)
           Initialize a SHAKE128 context.  Must be done before any other
           operations on ctx.

     SHAKE128_Update(ctx, data, len)
           Append len octets at data to the message.

     SHAKE128_Final(output, outlen, ctx)
           Store at output the first outlen octets of the SHAKE128 output for
           the message obtained by concatenating all prior inputs to
           SHAKE128_Update() on ctx.

           Subsequent use of ctx is not allowed, unless it is reinitialized
           with SHAKE128_Init().

SEE ALSO
     sha3(3), SHA3_Selftest(3)

STANDARDS
     National Institute of Standards and Technology, SHA-3 Standard:
     Permutation-Based Hash and Extendable-Output Functions, August 2015, FIPS
     PUB 202.

AUTHORS
     Taylor R Campbell <campbell+sha3@mumble.net>

Linux 7.0.3-arch1-2            October 14, 2015            Linux 7.0.3-arch1-2