---
name: "gnutls_hmac_fast"
section: "3"
platform: "linux"
package: "gnutls"
version: "3.8.13-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gnutls_hmac_fast"
---

# gnutls\_hmac\_fast(3)

API function

## NAME

gnutls\_hmac\_fast - API function

## SYNOPSIS

**#include \<gnutls/crypto.h\>**

**int gnutls\_hmac\_fast(gnutls\_mac\_algorithm\_t** *algorithm***, const void \*** *key***, size\_t** *keylen***, const void \*** *ptext***, size\_t** *ptext\_len***, void \*** *digest***);**

## ARGUMENTS

- gnutls\_mac\_algorithm\_t algorithm

  the hash algorithm to use

- const void \* key

  the key to use

- size\_t keylen

  the length of the key

- const void \* ptext

  the data to hash

- size\_t ptext\_len

  the length of data to hash

- void \* digest

  is the output value of the hash

## DESCRIPTION

This convenience function will hash the given data and return output on a single call. Note, this call will not work for MAC algorithms that require nonce (like UMAC or GMAC).

## RETURNS

Zero or a negative error code on error.

## SINCE

2\.10.0

## REPORTING BUGS

Report bugs to \<bugs@gnutls.org\>.\
 Home page: https://www.gnutls.org

## COPYRIGHT

Copyright © 2001-2023 Free Software Foundation, Inc., and others.\
 Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

## SEE ALSO

The full documentation for **gnutls** is maintained as a Texinfo manual. If the /usr/share/doc/gnutls/ directory does not contain the HTML form visit

- https://www.gnutls.org/manual/