NAME

       EVP_MAC-GMAC - The GMAC EVP_MAC implementation

DESCRIPTION

       Support for computing GMAC MACs through the EVP_MAC API.

       This implementation uses EVP_CIPHER functions to get access to the underlying cipher.

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

       "GMAC", "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).

       "iv" (OSSL_MAC_PARAM_IV) <octet string>
           Sets the IV of the underlying cipher, when applicable.

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

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

       The following parameters can be retrieved with EVP_MAC_CTX_get_params():

       "size" (OSSL_MAC_PARAM_SIZE) <unsigned integer>
           Gets the MAC size.

       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.

SEE ALSO

       EVP_MAC_CTX_get_params(3), EVP_MAC_CTX_set_params(3), "PARAMETERS" in EVP_MAC(3),
       OSSL_PARAM(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>.