NAME

       EVP_MD-BLAKE2 - The BLAKE2 EVP_MD implementation

DESCRIPTION

       Support for computing BLAKE2 digests through the EVP_MD API.

   Identities
       This implementation is only available with the default provider, and includes the following varieties:

       BLAKE2S-256
           Known names are "BLAKE2S-256" and "BLAKE2s256".

       BLAKE2B-512
           Known names are "BLAKE2B-512" and "BLAKE2b512".

   Settable Parameters
       "BLAKE2B-512"   supports   the   following  EVP_MD_CTX_set_params()  key  described  in  "PARAMETERS"  in
       EVP_DigestInit(3).

       "size" (OSSL_DIGEST_PARAM_SIZE) <unsigned integer>

   Gettable Parameters
       This implementation supports the common gettable parameters described in EVP_MD-common(7).

   Settable Context Parameters
       The implementation supports the following OSSL_PARAM(3) entries which are settable for an EVP_MD_CTX with
       EVP_DigestInit_ex2(3) or EVP_MD_CTX_set_params(3):

       "size" (OSSL_DIGEST_PARAM_SIZE) <unsigned integer>
           Sets a different digest length for the EVP_DigestFinal(3) output.  The value of the "size"  parameter
           must  not  exceed  the  default  digest  length  of  the respective BLAKE2 algorithm variants, 64 for
           BLAKE2B-512 and 32 for BLAKE2S-256. The parameter must be set with the EVP_DigestInit_ex2(3) call  to
           have  an  immediate effect. When set with EVP_MD_CTX_set_params(3) it will have an effect only if the
           EVP_MD_CTX context is reinitialized.

SEE ALSO

       provider-digest(7), OSSL_PROVIDER-default(7)

HISTORY

       This functionality was added in OpenSSL 3.0.

       The variable size support was added in OpenSSL 3.2 for BLAKE2B-512 and in OpenSSL 3.3 for BLAKE2S-256.

COPYRIGHT

       Copyright 2020-2024 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>.

3.5.0                                              2025-06-04                                EVP_MD-BLAKE2(7SSL)