.\"	$OpenBSD: X509_verify_cert.3,v 1.8 2019/06/06 01:06:59 schwarze Exp $
.\"	OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
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.Dd $Mdocdate: June 6 2019 $
.Dt X509_VERIFY_CERT 3
.Os
.Sh NAME
.Nm X509_verify_cert
.Nd discover and verify X509 certificate chain
.Sh SYNOPSIS
.In openssl/x509.h
.Ft int
.Fo X509_verify_cert
.Fa "X509_STORE_CTX *ctx"
.Fc
.Sh DESCRIPTION
The
.Fn X509_verify_cert
function attempts to discover and validate a certificate chain based on
parameters in
.Fa ctx .
.Pp
Applications rarely call this function directly, but it is used by
OpenSSL internally for certificate validation, in both the S/MIME and
SSL/TLS code.
.Sh RETURN VALUES
If a complete chain can be built and validated this function returns 1,
otherwise it returns a value <= 0 indicating failure.
.Pp
Additional error information can be obtained by examining
.Fa ctx ,
using
.Xr X509_STORE_CTX_get_error 3 .
.Sh SEE ALSO
.Xr openssl 1 ,
.Xr X509_STORE_CTX_get_error 3 ,
.Xr X509_STORE_CTX_new 3
.Sh HISTORY
.Fn X509_verify_cert
first appeared in SSLeay 0.8.0 and has been available since
.Ox 2.4 .
.Sh BUGS
This function uses the header
.In openssl/x509.h
as opposed to most chain verification functions which use
.In openssl/x509_vfy.h .