man > EVP_MAC-Poly1305(7)

EVP_MAC-POLY1305(7SSL)                         OpenSSL                        EVP_MAC-POLY1305(7SSL)

NAME
       EVP_MAC-Poly1305 - The Poly1305 EVP_MAC implementation

DESCRIPTION
       Support for computing Poly1305 MACs through the EVP_MAC API.

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

       "POLY1305", "provider=default"

   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).

       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 with EVP_MAC_CTX_get_mac_size().  The  length
       of the "size" parameter should not exceed that of an unsigned int.

NOTES
       The OpenSSL implementation of the Poly 1305 MAC corresponds to RFC 7539.

       It  is  critical  to never reuse the key.  The security implication noted in RFC 8439 applies
       equally to the OpenSSL implementation.

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>.

3.0.13                                       2026-07-29                       EVP_MAC-POLY1305(7SSL)