X509_CHECK_CA(3SSL) OpenSSL X509_CHECK_CA(3SSL)
NAME
X509_check_ca - check if given certificate is CA certificate
SYNOPSIS
#include <openssl/x509v3.h>
int X509_check_ca(X509 *cert);
DESCRIPTION
This function checks if given certificate is CA certificate (can be used
to sign other certificates). The certificate must be a complete
certificate otherwise an error is returned.
RETURN VALUES
Function return 0, if it is not CA certificate, 1 if it is proper X509v3
CA certificate with basicConstraints extension CA:TRUE, 3, if it is
self-signed X509 v1 certificate, 4, if it is certificate with keyUsage
extension with bit keyCertSign set, but without basicConstraints, and 5
if it has outdated Netscape Certificate Type extension telling that it
is CA certificate.
This function will also return 0 on error.
Actually, any nonzero value means that this certificate could have been
used to sign other certificates.
SEE ALSO
X509_verify_cert(3), X509_check_issued(3), X509_check_purpose(3)
COPYRIGHT
Copyright 2015-2021 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>.
3.5.7 2026-06-09 X509_CHECK_CA(3SSL)
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