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EVP_MD-BLAKE2.7ossl - Man Page

The BLAKE2 EVP_MD implementation


Support for computing BLAKE2 digests through the EVP_MD API.


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


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


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

Gettable Parameters

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

Settable Context Parameters

The BLAKE2B-512 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 (64 for BLAKE2B-512). 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)


This functionality was added in OpenSSL 3.0.

The variable size support was added in OpenSSL 3.2 for BLAKE2B-512.

Referenced By

EVP_blake2b512.3ossl(3), OSSL_PROVIDER-default.7ossl(7), provider-digest.7ossl(7).

2024-06-06 3.2.2 OpenSSL