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

# dane\_verify\_crt(3)

API function

## NAME

dane\_verify\_crt - API function

## SYNOPSIS

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

**int dane\_verify\_crt(dane\_state\_t** *s***, const gnutls\_datum\_t \*** *chain***, unsigned** *chain\_size***, gnutls\_certificate\_type\_t** *chain\_type***, const char \*** *hostname***, const char \*** *proto***, unsigned int** *port***, unsigned int** *sflags***, unsigned int** *vflags***, unsigned int \*** *verify***);**

## ARGUMENTS

- dane\_state\_t s

  A DANE state structure (may be NULL)

- const gnutls\_datum\_t \* chain

  A certificate chain

- unsigned chain\_size

  The size of the chain

- gnutls\_certificate\_type\_t chain\_type

  The type of the certificate chain

- const char \* hostname

  The hostname associated with the chain

- const char \* proto

  The protocol of the service connecting (e.g. tcp)

- unsigned int port

  The port of the service connecting (e.g. 443)

- unsigned int sflags

  Flags for the initialization of  *s* (if NULL)

- unsigned int vflags

  Verification flags; an OR'ed list of **dane\_verify\_flags\_t**.

- unsigned int \* verify

  An OR'ed list of **dane\_verify\_status\_t**.

## DESCRIPTION

This function will verify the given certificate chain against the CA constrains and/or the certificate available via DANE. If no information via DANE can be obtained the flag **DANE\_VERIFY\_NO\_DANE\_INFO** is set. If a DNSSEC signature is not available for the DANE record then the verify flag **DANE\_VERIFY\_NO\_DNSSEC\_DATA** is set.

Due to the many possible options of DANE, there is no single threat model countered. When notifying the user about DANE verification results it may be better to mention: DANE verification did not reject the certificate, rather than mentioning a successful DANE verification.

Note that this function is designed to be run in addition to PKIX - certificate chain - verification. To be run independently the **DANE\_VFLAG\_ONLY\_CHECK\_EE\_USAGE** flag should be specified; then the function will check whether the key of the peer matches the key advertised in the DANE entry.

## RETURNS

a negative error code on error and **DANE\_E\_SUCCESS** (0) when the DANE entries were successfully parsed, irrespective of whether they were verified (see  *verify* for that information). If no usable entries were encountered **DANE\_E\_REQUESTED\_DATA\_NOT\_AVAILABLE** will be returned.

## 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/