.\" $OpenBSD: EVP_PKEY_cmp.3,v 1.10 2019/06/06 01:06:58 schwarze Exp $ .\" OpenSSL 05ea606a May 20 20:52:46 2016 -0400 .\" .\" This file was written by Dr. Stephen Henson . .\" Copyright (c) 2006, 2013, 2014, 2016 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: June 6 2019 $ .Dt EVP_PKEY_CMP 3 .Os .Sh NAME .Nm EVP_PKEY_missing_parameters , .Nm EVP_PKEY_copy_parameters , .Nm EVP_PKEY_cmp_parameters , .Nm EVP_PKEY_cmp .Nd public key parameter and comparison functions .Sh SYNOPSIS .In openssl/evp.h .Ft int .Fo EVP_PKEY_missing_parameters .Fa "const EVP_PKEY *pkey" .Fc .Ft int .Fo EVP_PKEY_copy_parameters .Fa "EVP_PKEY *to" .Fa "const EVP_PKEY *from" .Fc .Ft int .Fo EVP_PKEY_cmp_parameters .Fa "const EVP_PKEY *a" .Fa "const EVP_PKEY *b" .Fc .Ft int .Fo EVP_PKEY_cmp .Fa "const EVP_PKEY *a" .Fa "const EVP_PKEY *b" .Fc .Sh DESCRIPTION The function .Fn EVP_PKEY_missing_parameters returns 1 if the public key parameters of .Fa pkey are missing and 0 if they are present or the algorithm doesn't use parameters. .Pp The function .Fn EVP_PKEY_copy_parameters copies the parameters from key .Fa from to key .Fa to . An error is returned if the parameters are missing in .Fa from . .Pp The function .Fn EVP_PKEY_cmp_parameters compares the parameters of keys .Fa a and .Fa b . .Pp The function .Fn EVP_PKEY_cmp compares the public key components and parameters (if present) of keys .Fa a and .Fa b . .Pp The main purpose of the functions .Fn EVP_PKEY_missing_parameters and .Fn EVP_PKEY_copy_parameters is to handle public keys in certificates where the parameters are sometimes omitted from a public key if they are inherited from the CA that signed it. .Pp Since OpenSSL private keys contain public key components too, the function .Fn EVP_PKEY_cmp can also be used to determine if a private key matches a public key. .Sh RETURN VALUES The function .Fn EVP_PKEY_missing_parameters returns 1 if the public key parameters of .Fa pkey are missing and 0 if they are present or the algorithm doesn't use parameters. .Pp The function .Fn EVP_PKEY_copy_parameters returns 1 for success and 0 for failure. .Pp The functions .Fn EVP_PKEY_cmp_parameters and .Fn EVP_PKEY_cmp return 1 if the keys match, 0 if they don't match, -1 if the key types are different and -2 if the operation is not supported. .Sh SEE ALSO .Xr EVP_PKEY_asn1_set_public 3 , .Xr EVP_PKEY_CTX_new 3 , .Xr EVP_PKEY_keygen 3 , .Xr EVP_PKEY_new 3 .Sh HISTORY .Fn EVP_PKEY_missing_parameters and .Fn EVP_PKEY_copy_parameters first appeared in SSLeay 0.8.0. .Fn EVP_PKEY_cmp_parameters first appeared in SSLeay 0.9.0. These functions have been available since .Ox 2.4 . .Pp .Fn EVP_PKEY_cmp first appeared in OpenSSL 0.9.8 and has been available since .Ox 4.5 .