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.\" ========================================================================
.\"
.IX Title "X509_CHECK_CA 3"
.TH X509_CHECK_CA 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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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 \s-1CA\s0 certificate (can be used
to sign other certificates).
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
Function return 0, if it is not \s-1CA\s0 certificate, 1 if it is proper X509v3
\&\s-1CA\s0 certificate with \fBbasicConstraints\fR extension \s-1CA:TRUE,
3,\s0 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\&\fBbasicConstraints\fR, and 5 if it has outdated Netscape Certificate Type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 \s-1CA\s0 certificate.
.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\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.