NAME

       EVP_MAC-HMAC - The HMAC EVP_MAC implementation

DESCRIPTION

       Support for computing HMAC MACs through the EVP_MAC API.

       This implementation uses EVP_MD functions to get access to the underlying digest.

   Identity
       This implementation is identified with this name and properties, to be used with EVP_MAC_fetch():

       "HMAC", "provider=default" or "provider=fips"

   Supported parameters
       The general description of these parameters can be found in "PARAMETERS" in EVP_MAC(3).

       The following parameter can be set with EVP_MAC_CTX_set_params():

       "key" (OSSL_MAC_PARAM_KEY) <octet string>
           Sets the MAC key.  Setting this parameter is identical to passing a key to EVP_MAC_init(3).

       "digest" (OSSL_MAC_PARAM_DIGEST) <UTF8 string>
           Sets the name of the underlying digest to be used.

       "properties" (OSSL_MAC_PARAM_PROPERTIES) <UTF8 string>
           Sets  the  properties  to  be queried when trying to fetch the underlying digest.  This must be given
           together with the digest naming parameter  ("digest",  or  OSSL_MAC_PARAM_DIGEST)  to  be  considered
           valid.

       "digest-noinit" (OSSL_MAC_PARAM_DIGEST_NOINIT) <integer>
           A flag to set the MAC digest to not initialise the implementation specific data.  The value 0 or 1 is
           expected.

       "digest-oneshot" (OSSL_MAC_PARAM_DIGEST_ONESHOT) <integer>
           A flag to set the MAC digest to be a one-shot operation.  The value 0 or 1 is expected.

       "tls-data-size" (OSSL_MAC_PARAM_TLS_DATA_SIZE) <unsigned integer>

       The following parameter can be retrieved with EVP_MAC_CTX_get_params():

       "size" (OSSL_MAC_PARAM_SIZE) <unsigned integer>
           The "size" parameter can also be retrieved with EVP_MAC_CTX_get_mac_size().  The length of the "size"
           parameter is equal to that of an unsigned int.

       "block-size" (OSSL_MAC_PARAM_BLOCK_SIZE) <unsigned integer>
           Gets   the   MAC   block   size.    The   "block-size"   parameter   can   also   be  retrieved  with
           EVP_MAC_CTX_get_block_size().

SEE ALSO

       EVP_MAC_CTX_get_params(3), EVP_MAC_CTX_set_params(3), "PARAMETERS" in EVP_MAC(3), OSSL_PARAM(3), HMAC(3)

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>.

3.0.13                                             2025-02-05                                 EVP_MAC-HMAC(7SSL)