SSL_get_peer_certificate, SSL_get0_peer_certificate, SSL_get1_peer_certificate - get the X509 certificate of the peer

#include <openssl/ssl.h>
X509 *SSL_get_peer_certificate(const SSL *ssl);
X509 *SSL_get0_peer_certificate(const SSL *ssl);
X509 *SSL_get1_peer_certificate(const SSL *ssl);

These functions return a pointer to the X509 certificate the peer presented. If the peer did not present a certificate, NULL is returned.

Due to the protocol definition, a TLS/SSL server will always send a certificate, if present. A client will only send a certificate when explicitly requested to do so by the server (see SSL_CTX_set_verify(3)). If an anonymous cipher is used, no certificates are sent.

That a certificate is returned does not indicate information about the verification state, use SSL_get_verify_result(3) to check the verification state.

The reference count of the X509 object returned by SSL_get1_peer_certificate() is incremented by one, so that it will not be destroyed when the session containing the peer certificate is freed. The X509 object must be explicitly freed using X509_free().

The reference count of the X509 object returned by SSL_get0_peer_certificate() is not incremented, and must not be freed.

SSL_get_peer_certificate() is an alias of SSL_get1_peer_certificate().

The following return values can occur:

No certificate was presented by the peer or no connection was established.
The return value points to the certificate presented by the peer.

ssl(7), SSL_get_verify_result(3), SSL_CTX_set_verify(3)

SSL_get0_peer_certificate() and SSL_get1_peer_certificate() were added in 3.0.0. SSL_get_peer_certificate() was deprecated in 3.0.0.

Copyright 2000-2020 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

2023-10-24 3.1.4