.\"	$OpenBSD: X509_check_private_key.3,v 1.2 2018/03/21 03:16:08 schwarze Exp $
.\"	OpenSSL X509_check_private_key.pod 09ddb878 Jun 5 03:56:07 2017 +0800
.\"
.\" Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
.\"
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.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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.\"
.Dd $Mdocdate: March 21 2018 $
.Dt X509_CHECK_PRIVATE_KEY 3
.Os
.Sh NAME
.Nm X509_check_private_key ,
.Nm X509_REQ_check_private_key
.Nd compare public key components
.Sh SYNOPSIS
.In openssl/x509.h
.Ft int
.Fo X509_check_private_key
.Fa "X509 *x"
.Fa "EVP_PKEY *k"
.Fc
.Ft int
.Fo X509_REQ_check_private_key
.Fa "X509_REQ *x"
.Fa "EVP_PKEY *k"
.Fc
.Sh DESCRIPTION
These functions are seriously misnamed.
.Fn X509_check_private_key
compares the
.Em public
key components (e.g. exponent and modulus of an RSA key)
and parameters (e.g. EC params of an EC key) of
.Fa k
with the corresponding properties of
.Fa x .
Despite the name, it neither checks whether
.Fa k
contains private key components at all, nor, if any are present,
whether they are consistent with the public key components.
.Pp
.Fn X509_REQ_check_private_key
is equivalent to
.Fn X509_check_private_key
except that it compares to the public key
contained in a certificate request.
.Sh RETURN VALUES
These functions return 1 if the public key components and parameters
match, or 0 if they do not or if an error occurs.
On error or mismatch, a reason code can be obtained using
.Xr ERR_get_error 3 .
.Sh SEE ALSO
.Xr SSL_check_private_key 3
.Sh HISTORY
.Fn X509_check_private_key
appeared before SSLeay 0.8 and has been available since
.Ox 2.4 .