.\" $OpenBSD: EVP_PKEY_cmp.3,v 1.13 2023/09/08 11:37:58 schwarze Exp $ .\" full merge up to: OpenSSL 05ea606a May 20 20:52:46 2016 -0400 .\" selective merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2021 Ingo Schwarze .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. 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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: September 8 2023 $ .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 .\" .Nm EVP_PKEY_save_parameters is intentionally undocumented .\" because nothing uses it according to codesearch.debian.net .\" and it only affects X509_PUBKEY_set(3) for DSA and GOST2001 keys, .\" resulting in incomplete output without the public key parameters. .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 *destination" .Fa "const EVP_PKEY *source" .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 .Fn EVP_PKEY_missing_parameters checks whether any public key parameters are missing from .Fa pkey . .Pp .Fn EVP_PKEY_copy_parameters copies all public key parameters from the .Fa source to the .Fa destination . If the algorithm does not use parameters, no action occurs. .Pp .Fn EVP_PKEY_cmp_parameters compares the public key parameters of .Fa a and .Fa b . This is only supported for algorithms that use parameters. .Pp .Fn EVP_PKEY_cmp compares the public key components of .Fa a and .Fa b . If the algorithm uses public key parameters, it also compares the parameters. .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 .Fn EVP_PKEY_missing_parameters returns 1 if the public key parameters of .Fa pkey are missing or incomplete or 0 if they are present and complete or if the algorithm doesn't use parameters. .Pp .Fn EVP_PKEY_copy_parameters returns 1 for success or 0 for failure. In particular, it fails if the key types mismatch or if the public key parameters in the .Fa source are missing or incomplete. .Pp .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 , .Xr X509_get_pubkey_parameters 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 .