.\"	$OpenBSD: x509.3,v 1.4 2016/12/08 21:48:50 jmc Exp $
.\"	OpenSSL a9c85cea Nov 11 09:33:55 2016 +0100
.\"
.\" This file was written by Richard Levitte <levitte@openssl.org>
.\" Copyright (c) 2003 The OpenSSL Project.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in
.\"    the documentation and/or other materials provided with the
.\"    distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\"    software must display the following acknowledgment:
.\"    "This product includes software developed by the OpenSSL Project
.\"    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\"    endorse or promote products derived from this software without
.\"    prior written permission. For written permission, please contact
.\"    openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\"    nor may "OpenSSL" appear in their names without prior written
.\"    permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\"    acknowledgment:
.\"    "This product includes software developed by the OpenSSL Project
.\"    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: December 8 2016 $
.Dt X509 3
.Os
.Sh NAME
.Nm x509
.Nd X.509 certificate handling
.Sh SYNOPSIS
.In openssl/x509.h
.Sh DESCRIPTION
A X.509 certificate is a structured grouping of information about an
individual, a device, or anything one can imagine.
A X.509 CRL (certificate revocation list) is a tool to help determine if
a certificate is still valid.
The exact definition of those can be found in the X.509 document from
ITU-T, or in RFC 3280 from PKIX.
In OpenSSL, the type
.Vt X509
is used to express such a certificate, and the type
.Vt X509_CRL
is used to express a CRL.
.Pp
A related structure is a certificate request, defined in PKCS#10 from
RSA Security, Inc., also reflected in RFC 2896.
In OpenSSL, the type
.Vt X509_REQ
is used to express such a certificate request.
.Pp
To handle some complex parts of a certificate, there are the types
.Vt X509_NAME
to express a certificate name,
.Vt X509_ATTRIBUTE
to express a certificate attribute,
.Vt X509_EXTENSION
to express a certificate extension, and a few more.
.Pp
Finally, there's the supertype
.Vt X509_INFO ,
which can contain a CRL, a certificate, and a corresponding private key.
.Pp
The functions
.Fa X509_* ,
.Fa d2i_X509_* ,
and
.Fa i2d_X509_*
handle X.509 certificates, with some exceptions shown below.
.Pp
.Fa X509_CRL_* ,
.Fa d2i_X509_CRL_* ,
and
.Fa i2d_X509_CRL_*
handle X.509 CRLs.
.Pp
.Fa X509_REQ_* ,
.Fa d2i_X509_REQ_* ,
and
.Fa i2d_X509_REQ_*
handle PKCS#10 certificate requests.
.Pp
.Fa X509_NAME_*
handle certificate names.
.Pp
.Fa X509_ATTRIBUTE_*
handle certificate attributes.
.Pp
.Fa X509_EXTENSION_*
handle certificate extensions.
.Sh SEE ALSO
.Xr crypto 3 ,
.Xr d2i_X509 3 ,
.Xr d2i_X509_ALGOR 3 ,
.Xr d2i_X509_CRL 3 ,
.Xr d2i_X509_NAME 3 ,
.Xr d2i_X509_REQ 3 ,
.Xr d2i_X509_SIG 3 ,
.Xr X509_NAME_add_entry_by_NID 3 ,
.Xr X509_NAME_add_entry_by_txt 3 ,
.Xr X509_NAME_ENTRY_get_object 3 ,
.Xr X509_NAME_new 3 ,
.Xr X509_NAME_print_ex 3