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.\"
.IX Title "X509_CHECK_CA 3ssl"
.TH X509_CHECK_CA 3ssl 2024-10-23 3.4.0 OpenSSL
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH NAME
X509_check_ca \- check if given certificate is CA certificate
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/x509v3.h>
\&
\& int X509_check_ca(X509 *cert);
.Ve
.SH DESCRIPTION
.IX Header "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.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
Function return 0, if it is not CA certificate, 1 if it is proper X509v3
CA certificate with \fBbasicConstraints\fR extension CA:TRUE,
3, if it is self-signed X509 v1 certificate, 4, if it is certificate with
\&\fBkeyUsage\fR extension with bit \fBkeyCertSign\fR set, but without
\&\fBbasicConstraints\fR, and 5 if it has outdated Netscape Certificate Type
extension telling that it is CA certificate.
.PP
This function will also return 0 on error.
.PP
Actually, any nonzero value means that this certificate could have been
used to sign other certificates.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBX509_verify_cert\fR\|(3),
\&\fBX509_check_issued\fR\|(3),
\&\fBX509_check_purpose\fR\|(3)
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright 2015\-2021 The OpenSSL Project Authors. All Rights Reserved.
.PP
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>.