---
name: "gnutls_x509_crt_get_pk_algorithm"
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_x509_crt_get_pk_algorithm"
---

# gnutls\_x509\_crt\_get\_pk\_algorithm(3)

API function

## NAME

gnutls\_x509\_crt\_get\_pk\_algorithm - API function

## SYNOPSIS

**#include \<gnutls/x509.h\>**

**int gnutls\_x509\_crt\_get\_pk\_algorithm(gnutls\_x509\_crt\_t** *cert***, unsigned int \*** *bits***);**

## ARGUMENTS

- gnutls\_x509\_crt\_t cert

  should contain a **gnutls\_x509\_crt\_t** type

- unsigned int \* bits

  if bits is non null it will hold the size of the parameters' in bits

## DESCRIPTION

This function will return the public key algorithm of an X.509 certificate.

If bits is non null, it should have enough size to hold the parameters size in bits. For RSA the bits returned is the modulus. For DSA the bits returned are of the public exponent.

Unknown/unsupported algorithms are mapped to **GNUTLS\_PK\_UNKNOWN**.

## RETURNS

a member of the **gnutls\_pk\_algorithm\_t** enumeration on success, or a negative error code on error.

## 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/