---
name: "EVP_MD-BLAKE2"
section: "7ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/EVP_MD-BLAKE2"
---

# EVP\_MD-BLAKE2(7ssl)

The BLAKE2 EVP\_MD implementation

## 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\>.