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.\" ========================================================================
.\"
.IX Title "X509_CHECK_PURPOSE 3"
.TH X509_CHECK_PURPOSE 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.nh
.SH "NAME"
X509_check_purpose \- Check the purpose of a certificate
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/x509v3.h>
\&
\& int X509_check_purpose(X509 *x, int id, int ca)
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This function checks if certificate \fIx\fR was created with the purpose
represented by \fIid\fR. If \fIca\fR is nonzero, then certificate \fIx\fR is
checked to determine if it's a possible \s-1CA\s0 with various levels of certainty
possibly returned.
.PP
Below are the potential \s-1ID\s0's that can be checked:
.PP
.Vb 9
\& # define X509_PURPOSE_SSL_CLIENT        1
\& # define X509_PURPOSE_SSL_SERVER        2
\& # define X509_PURPOSE_NS_SSL_SERVER     3
\& # define X509_PURPOSE_SMIME_SIGN        4
\& # define X509_PURPOSE_SMIME_ENCRYPT     5
\& # define X509_PURPOSE_CRL_SIGN          6
\& # define X509_PURPOSE_ANY               7
\& # define X509_PURPOSE_OCSP_HELPER       8
\& # define X509_PURPOSE_TIMESTAMP_SIGN    9
.Ve
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
For non-CA checks
.IP "\-1 an error condition has occurred" 4
.IX Item "-1 an error condition has occurred"
.PD 0
.IP " 1 if the certificate was created to perform the purpose represented by \fIid\fR" 4
.IX Item " 1 if the certificate was created to perform the purpose represented by id"
.IP " 0 if the certificate was not created to perform the purpose represented by \fIid\fR" 4
.IX Item " 0 if the certificate was not created to perform the purpose represented by id"
.PD
.PP
For \s-1CA\s0 checks the below integers could be returned with the following meanings:
.IP "\-1 an error condition has occurred" 4
.IX Item "-1 an error condition has occurred"
.PD 0
.IP " 0 not a \s-1CA\s0 or does not have the purpose represented by \fIid\fR" 4
.IX Item " 0 not a CA or does not have the purpose represented by id"
.IP " 1 is a \s-1CA.\s0" 4
.IX Item " 1 is a CA."
.IP " 2 Only possible in old versions of openSSL when basicConstraints are absent. New versions will not return this value. May be a \s-1CA\s0" 4
.IX Item " 2 Only possible in old versions of openSSL when basicConstraints are absent. New versions will not return this value. May be a CA"
.IP " 3 basicConstraints absent but self signed V1." 4
.IX Item " 3 basicConstraints absent but self signed V1."
.IP " 4 basicConstraints absent but keyUsage present and keyCertSign asserted." 4
.IX Item " 4 basicConstraints absent but keyUsage present and keyCertSign asserted."
.IP " 5 legacy Netscape specific \s-1CA\s0 Flags present" 4
.IX Item " 5 legacy Netscape specific CA Flags present"
.PD
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2019\-2020 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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>.