doc/man7/EVP_MD-SHAKE.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 EVP_MD-SHAKE, EVP_MD-KECCAK-KMAC
   6 - The SHAKE / KECCAK family EVP_MD implementations
   7
   8 =head1 DESCRIPTION
   9
  10 Support for computing SHAKE or KECCAK-KMAC digests through the
  11 B<EVP_MD> API.
  12
  13 KECCAK-KMAC is a special digest that's used by the KMAC EVP_MAC
  14 implementation (see L<EVP_MAC-KMAC(7)>).
  15
  16 =head2 Identities
  17
  18 This implementation is available in the FIPS provider as well as the default
  19 provider, and includes the following varieties:
  20
  21 =over 4
  22
  23 =item KECCAK-KMAC-128
  24
  25 Known names are "KECCAK-KMAC-128" and "KECCAK-KMAC128"
  26 This is used by L<EVP_MAC-KMAC128(7)>
  27
  28 =item KECCAK-KMAC-256
  29
  30 Known names are "KECCAK-KMAC-256" and "KECCAK-KMAC256"
  31 This is used by L<EVP_MAC-KMAC256(7)>
  32
  33 =item SHAKE-128
  34
  35 Known names are "SHAKE-128" and "SHAKE128"
  36
  37 =item SHAKE-256
  38
  39 Known names are "SHAKE-256" and "SHAKE256"
  40
  41 =back
  42
  43 =head2 Gettable Parameters
  44
  45 This implementation supports the common gettable parameters described
  46 in L<EVP_MD-common(7)>.
  47
  48 =head2 Settable Context Parameters
  49
  50 These implementations support the following L<OSSL_PARAM(3)> entries,
  51 settable for an B<EVP_MD_CTX> with L<EVP_MD_CTX_set_params(3)>:
  52
  53 =over 4
  54
  55 =item "xoflen" (B<OSSL_DIGEST_PARAM_XOFLEN>) <unsigned integer>
  56
  57 Sets the digest length for extendable output functions.
  58 The length of the "xoflen" parameter should not exceed that of a B<size_t>.
  59
  60 For backwards compatibility reasons the default xoflen length for SHAKE-128 is
  61 16 (bytes) which results in a security strength of only 64 bits. To ensure the
  62 maximum security strength of 128 bits, the xoflen should be set to at least 32.
  63
  64 For backwards compatibility reasons the default xoflen length for SHAKE-256 is
  65 32 (bytes) which results in a security strength of only 128 bits. To ensure the
  66 maximum security strength of 256 bits, the xoflen should be set to at least 64.
  67
  68 =back
  69
  70 =head1 SEE ALSO
  71
  72 L<EVP_MD_CTX_set_params(3)>, L<provider-digest(7)>, L<OSSL_PROVIDER-default(7)>
  73
  74 =head1 COPYRIGHT
  75
  76 Copyright 2020-2022 The OpenSSL Project Authors. All Rights Reserved.
  77
  78 Licensed under the Apache License 2.0 (the "License").  You may not use
  79 this file except in compliance with the License.  You can obtain a copy
  80 in the file LICENSE in the source distribution or at
  81 L<https://www.openssl.org/source/license.html>.
  82
  83 =cut