# EVP_MAC-Siphash - The Siphash EVP_MAC implementation - man(7ssl) - [phpMan]

[_EVP_MAC-SIPHASH_(7SSL)](https://www.chedong.com/phpMan.php/man/EVPMAC-SIPHASH/7SSL/markdown)                          OpenSSL                         [_EVP_MAC-SIPHASH_(7SSL)](https://www.chedong.com/phpMan.php/man/EVPMAC-SIPHASH/7SSL/markdown)

## NAME
       EVP_MAC-Siphash - The Siphash EVP_MAC implementation

## DESCRIPTION
       Support for computing Siphash MACs through the **EVP_MAC **API.

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

       "SIPHASH", "provider=default"

### Supported parameters
       The general description of these parameters can be found in "PARAMETERS" in [**EVP_MAC**(3)](https://www.chedong.com/phpMan.php/man/EVPMAC/3/markdown).

       All  these  parameters  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**.

       "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)](https://www.chedong.com/phpMan.php/man/EVPMACinit/3/markdown).

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

       "c-rounds" (**OSSL_MAC_PARAM_C_ROUNDS**) <unsigned integer>
           Specifies the number of rounds per message block.  By default this is _2_.

       "d-rounds" (**OSSL_MAC_PARAM_D_ROUNDS**) <unsigned integer>
           Specifies the number of finalisation rounds.  By default this is _4_.

## SEE ALSO
       [**EVP_MAC_CTX_get_params**(3)](https://www.chedong.com/phpMan.php/man/EVPMACCTXgetparams/3/markdown),    [**EVP_MAC_CTX_set_params**(3)](https://www.chedong.com/phpMan.php/man/EVPMACCTXsetparams/3/markdown),    "PARAMETERS"    in    [**EVP_MAC**(3)](https://www.chedong.com/phpMan.php/man/EVPMAC/3/markdown),
       [**OSSL_PARAM**(3)](https://www.chedong.com/phpMan.php/man/OSSLPARAM/3/markdown)

## 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-SIPHASH_(7SSL)](https://www.chedong.com/phpMan.php/man/EVPMAC-SIPHASH/7SSL/markdown)