---
name: "EVP_SIGNATURE-HMAC"
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_SIGNATURE-HMAC"
---

# EVP\_SIGNATURE-HMAC(7ssl)

The legacy EVP\_PKEY MAC signature implementations

## NAME

EVP\_SIGNATURE-HMAC, EVP\_SIGNATURE-Siphash, EVP\_SIGNATURE-Poly1305, EVP\_SIGNATURE-CMAC - The legacy EVP\_PKEY MAC signature implementations

## DESCRIPTION

The algorithms described here have legacy support for creating MACs using **EVP\_DigestSignInit**(3) and related functions. This is not the preferred way of creating MACs. Instead you should use the newer **EVP\_MAC\_init**(3) functions. This mechanism is provided for backwards compatibility with older versions of OpenSSL.

The same signature parameters can be set using **EVP\_PKEY\_CTX\_set\_params()** as can be set via **EVP\_MAC\_CTX\_set\_params()** for the underlying EVP\_MAC. See **EVP\_MAC-HMAC**(7), **EVP\_MAC-Siphash**(7), **EVP\_MAC-Poly1305**(7) and **EVP\_MAC-CMAC**(7) for details.

```
 See L<EVP_PKEY-HMAC(7)>, L<EVP_PKEY-Siphash(7)>, L<EVP_PKEY-Poly1305(7)> or
 L<EVP_PKEY-CMAC(7)> for details about parameters that are supported during the
 creation of an EVP_PKEY.
```

For HMAC and CMAC, the OpenSSL FIPS provider also makes the following parameter available with **EVP\_PKEY\_CTX\_get\_params**(3):

- "fips-indicator" (**OSSL\_SIGNATURE\_PARAM\_FIPS\_APPROVED\_INDICATOR**) \<integer\>

  Returns 1 if the operation is FIPS approved, or 0 otherwise. See "FIPS indicators" in **fips\_module**(7) for more information.

## SEE ALSO

**EVP\_MAC\_init**(3), **EVP\_DigestSignInit**(3), **EVP\_PKEY-HMAC**(7), **EVP\_PKEY-Siphash**(7), **EVP\_PKEY-Poly1305**(7), **EVP\_PKEY-CMAC**(7), **EVP\_MAC-HMAC**(7), **EVP\_MAC-Siphash**(7), **EVP\_MAC-Poly1305**(7), **EVP\_MAC-CMAC**(7), **provider-signature**(7),

## COPYRIGHT

Copyright 2020-2026 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\>.