EVP_MAC-BLAKE2(7SSL) OpenSSL EVP_MAC-BLAKE2(7SSL)
NAME
EVP_MAC-BLAKE2, EVP_MAC-BLAKE2BMAC, EVP_MAC-BLAKE2SMAC - The BLAKE2
EVP_MAC implementations
DESCRIPTION
Support for computing BLAKE2 MACs through the EVP_MAC API.
Identity
These implementations are identified with one of these names and
properties, to be used with EVP_MAC_fetch():
"BLAKE2BMAC", "provider=default"
"BLAKE2SMAC", "provider=default"
Supported parameters
The general description of these parameters can be found in "PARAMETERS"
in EVP_MAC(3).
All these parameters (except for "block-size") can be set with
EVP_MAC_CTX_set_params(). Furthermore, the "size" parameter can be
retrieved with EVP_MAC_CTX_get_params(), or with
EVP_MAC_CTX_get_mac_size(). The length of the "size" parameter should
not exceed that of a size_t. Likewise, the "block-size" parameter can
be retrieved with EVP_MAC_CTX_get_params(), or with
EVP_MAC_CTX_get_block_size().
"key" (OSSL_MAC_PARAM_KEY) <octet string>
Sets the MAC key. It may be at most 64 bytes for BLAKE2BMAC or 32
for BLAKE2SMAC and at least 1 byte in both cases. Setting this
parameter is identical to passing a key to EVP_MAC_init(3).
"custom" (OSSL_MAC_PARAM_CUSTOM) <octet string>
Sets the customization/personalization string. It is an optional
value of at most 16 bytes for BLAKE2BMAC or 8 for BLAKE2SMAC, and is
empty by default.
"salt" (OSSL_MAC_PARAM_SALT) <octet string>
Sets the salt. It is an optional value of at most 16 bytes for
BLAKE2BMAC or 8 for BLAKE2SMAC, and is empty by default.
"size" (OSSL_MAC_PARAM_SIZE) <unsigned integer>
Sets the MAC size. It can be any number between 1 and 32 for
EVP_MAC_BLAKE2S or between 1 and 64 for EVP_MAC_BLAKE2B. It is 32
and 64 respectively by default.
"block-size" (OSSL_MAC_PARAM_BLOCK_SIZE) <unsigned integer>
Gets the MAC block size. It is 64 for EVP_MAC_BLAKE2S and 128 for
EVP_MAC_BLAKE2B.
SEE ALSO
EVP_MAC_CTX_get_params(3), EVP_MAC_CTX_set_params(3), "PARAMETERS" in
EVP_MAC(3), OSSL_PARAM(3)
HISTORY
The macros and functions described here were added to OpenSSL 3.0.
COPYRIGHT
Copyright 2018-2021 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
<https://www.openssl.org/source/license.html>.
3.5.4 2025-09-30 EVP_MAC-BLAKE2(7SSL)
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