mirror of
https://github.com/openssl/openssl.git
synced 2025-03-07 19:38:33 +08:00
c48e56874c
Added the function EVP_MD_CTX_get_size_ex() which checks for XOF and does a ctx get rather than just returning EVP_MD_size(). SHAKE did not have a get_ctx_params() so that had to be added to return the xoflen. Added a helper function EVP_MD_xof() EVP_MD_CTX_size() was just an aliased macro for EVP_MD_size(), so to keep it the same I added an extra function. EVP_MD_size() always returns 0 for SHAKE now, since it caches the value of md_size at the time of an EVP_MD_fetch(). This is probably better than returning the incorrect initial value it was before e.g (16 for SHAKE128) and returning tht always instead of the set xoflen. Note BLAKE2B uses "size" instead of "xoflen" to do a similar thing. Reviewed-by: Matt Caswell <matt@openssl.org> Reviewed-by: Tomas Mraz <tomas@openssl.org> (Merged from https://github.com/openssl/openssl/pull/25285)
102 lines
2.8 KiB
Plaintext
102 lines
2.8 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
EVP_MD-SHAKE, EVP_MD-KECCAK-KMAC
|
|
- The SHAKE / KECCAK family EVP_MD implementations
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
Support for computing SHAKE or KECCAK-KMAC digests through the
|
|
B<EVP_MD> API.
|
|
|
|
KECCAK-KMAC is an Extendable Output Function (XOF), with a definition
|
|
similar to SHAKE, used by the KMAC EVP_MAC implementation (see
|
|
L<EVP_MAC-KMAC(7)>).
|
|
|
|
=head2 Identities
|
|
|
|
This implementation is available in the FIPS provider as well as the default
|
|
provider, and includes the following varieties:
|
|
|
|
=over 4
|
|
|
|
=item KECCAK-KMAC-128
|
|
|
|
Known names are "KECCAK-KMAC-128" and "KECCAK-KMAC128". This is used
|
|
by L<EVP_MAC-KMAC128(7)>. Using the notation from NIST FIPS 202
|
|
(Section 6.2), we have S<KECCAK-KMAC-128(M, d)> = S<KECCAK[256](M || 00, d)>
|
|
(see the description of KMAC128 in Appendix A of NIST SP 800-185).
|
|
|
|
=item KECCAK-KMAC-256
|
|
|
|
Known names are "KECCAK-KMAC-256" and "KECCAK-KMAC256". This is used
|
|
by L<EVP_MAC-KMAC256(7)>. Using the notation from NIST FIPS 202
|
|
(Section 6.2), we have S<KECCAK-KMAC-256(M, d)> = S<KECCAK[512](M || 00, d)>
|
|
(see the description of KMAC256 in Appendix A of NIST SP 800-185).
|
|
|
|
=item SHAKE-128
|
|
|
|
Known names are "SHAKE-128" and "SHAKE128".
|
|
|
|
=item SHAKE-256
|
|
|
|
Known names are "SHAKE-256" and "SHAKE256".
|
|
|
|
=back
|
|
|
|
=head2 Parameters
|
|
|
|
This implementation supports the following L<OSSL_PARAM(3)> entries:
|
|
|
|
=over 4
|
|
|
|
=item "xoflen" (B<OSSL_DIGEST_PARAM_XOFLEN>) <unsigned integer>
|
|
|
|
Sets or Gets the digest length for extendable output functions.
|
|
The length of the "xoflen" parameter should not exceed that of a B<size_t>.
|
|
|
|
The SHAKE-128 and SHAKE-256 implementations do not have any default digest
|
|
length.
|
|
|
|
This parameter must be set before calling either EVP_DigestFinal_ex() or
|
|
EVP_DigestFinal(), since these functions were not designed to handle variable
|
|
length output. It is recommended to either use EVP_DigestSqueeze() or
|
|
EVP_DigestFinalXOF() instead.
|
|
|
|
=item "size" (B<OSSL_DIGEST_PARAM_SIZE>) <unsigned integer>
|
|
|
|
An alias of "xoflen".
|
|
|
|
=back
|
|
|
|
See L<EVP_DigestInit(3)/PARAMETERS> for further information related to parameters
|
|
|
|
=head1 NOTES
|
|
|
|
For SHAKE-128, to ensure the maximum security strength of 128 bits, the output
|
|
length passed to EVP_DigestFinalXOF() should be at least 32.
|
|
|
|
For SHAKE-256, to ensure the maximum security strength of 256 bits, the output
|
|
length passed to EVP_DigestFinalXOF() should be at least 64.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<EVP_MD_CTX_set_params(3)>, L<provider-digest(7)>, L<OSSL_PROVIDER-default(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
Since OpenSSL 3.4 the SHAKE-128 and SHAKE-256 implementations have no default
|
|
digest length.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2020-2023 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
Licensed under the Apache License 2.0 (the "License"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file LICENSE in the source distribution or at
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|