.\" $OpenBSD: X509_get_pubkey.3,v 1.5 2018/03/27 17:35:50 schwarze Exp $
.\" selective merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
.\" Copyright (c) 2015 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: March 27 2018 $
.Dt X509_GET_PUBKEY 3
.Os
.Sh NAME
.Nm X509_get_pubkey ,
.Nm X509_get0_pubkey ,
.Nm X509_set_pubkey ,
.Nm X509_get_X509_PUBKEY ,
.Nm X509_REQ_get_pubkey ,
.Nm X509_REQ_set_pubkey
.Nd get or set certificate or certificate request public key
.Sh SYNOPSIS
.In openssl/x509.h
.Ft EVP_PKEY *
.Fo X509_get_pubkey
.Fa "X509 *x"
.Fc
.Ft EVP_PKEY *
.Fo X509_get0_pubkey
.Fa "const X509 *x"
.Fc
.Ft int
.Fo X509_set_pubkey
.Fa "X509 *x"
.Fa "EVP_PKEY *pkey"
.Fc
.Ft X509_PUBKEY *
.Fo X509_get_X509_PUBKEY
.Fa "X509 *x"
.Fc
.Ft EVP_PKEY *
.Fo X509_REQ_get_pubkey
.Fa "X509_REQ *req"
.Fc
.Ft int
.Fo X509_REQ_set_pubkey
.Fa "X509_REQ *x"
.Fa "EVP_PKEY *pkey"
.Fc
.Sh DESCRIPTION
.Fn X509_get_pubkey
attempts to decode the public key for certificate
.Fa x .
If successful it returns the public key as an
.Vt EVP_PKEY
pointer with its reference count incremented: this means the returned
key must be freed up after use.
.Fn X509_get0_pubkey
is similar except that it does not increment the reference count
of the returned
.Vt EVP_PKEY ,
so it must not be freed up after use.
.Pp
.Fn X509_get_X509_PUBKEY
returns an internal pointer to the
.Vt X509_PUBKEY
structure which encodes the certificate of
.Fa x .
The returned value must not be freed up after use.
.Fn X509_get_X509_PUBKEY
is implemented as a macro.
.Pp
.Fn X509_set_pubkey
attempts to set the public key for certificate
.Fa x
to
.Fa pkey .
The key
.Fa pkey
should be freed up after use.
.Pp
.Fn X509_REQ_get_pubkey
and
.Fn X509_REQ_set_pubkey
are similar but operate on certificate request
.Fa req .
.Pp
The first time a public key is decoded, the
.Vt EVP_PKEY
structure is cached in the certificate or certificate request itself.
Subsequent calls return the cached structure with its reference count
incremented to improve performance.
.Sh RETURN VALUES
.Fn X509_get_pubkey ,
.Fn X509_get0_pubkey ,
.Fn X509_get_X509_PUBKEY ,
and
.Fn X509_REQ_get_pubkey
return a public key or
.Dv NULL
if an error occurred.
.Pp
.Fn X509_set_pubkey
and
.Fn X509_REQ_set_pubkey
return 1 for success or 0 for failure.
.Sh SEE ALSO
.Xr d2i_X509 3 ,
.Xr ERR_get_error 3 ,
.Xr X509_CRL_get0_by_serial 3 ,
.Xr X509_NAME_add_entry_by_txt 3 ,
.Xr X509_NAME_ENTRY_get_object 3 ,
.Xr X509_NAME_get_index_by_NID 3 ,
.Xr X509_NAME_print_ex 3 ,
.Xr X509_new 3 ,
.Xr X509_sign 3 ,
.Xr X509_verify_cert 3 ,
.Xr X509V3_get_d2i 3
.Sh HISTORY
.Fn X509_get_pubkey ,
.Fn X509_set_pubkey ,
.Fn X509_REQ_get_pubkey ,
and
.Fn X509_REQ_set_pubkey
first appeared in SSLeay 0.6.5.
.Fn X509_get_X509_PUBKEY
first appeared in SSLeay 0.8.0.
These functions have been available since
.Ox 2.4 .
.Pp
.Fn X509_get0_pubkey
first appeared in OpenSSL 1.1.0 and has been available since
.Ox 6.3 .