.\" $OpenBSD: EVP_PKEY_get_default_digest_nid.3,v 1.9 2024/04/18 16:33:33 tb Exp $ .\" full merge up to: OpenSSL df75c2bf Dec 9 01:02:36 2018 +0100 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2023 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 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: April 18 2024 $ .Dt EVP_PKEY_GET_DEFAULT_DIGEST_NID 3 .Os .Sh NAME .Nm EVP_PKEY_get_default_digest_nid .Nd get default signature digest .Sh SYNOPSIS .In openssl/evp.h .Ft int .Fo EVP_PKEY_get_default_digest_nid .Fa "EVP_PKEY *pkey" .Fa "int *pnid" .Fc .Sh DESCRIPTION The .Fn EVP_PKEY_get_default_digest_nid function sets .Pf * Fa pnid to the default message digest NID for the public key signature operations associated with .Fa pkey . .Pp Some signature algorithms, for example .Dv EVP_PKEY_ED25519 , do not use a digest during signing. In this case, .Pf * Fa pnid is set to .Dv NID_undef . .Pp Support for the following public key algorithms is built into the library: .Pp .Bl -column -compact EVP_PKEY_base_id(3) NID_sha256 mandatory .It Xr EVP_PKEY_base_id 3 Ta Pf * Fa pnid Ta return value .It Dv EVP_PKEY_DSA Ta Dv NID_sha1 Ta mandatory .It Dv EVP_PKEY_EC Ta Dv NID_sha1 Ta mandatory .It Dv EVP_PKEY_ED25519 Ta Dv NID_undef Ta mandatory .It Dv EVP_PKEY_HMAC Ta Dv NID_sha1 Ta advisory .It Dv EVP_PKEY_RSA Ta Dv NID_sha256 Ta advisory .El .Sh RETURN VALUES The .Fn EVP_PKEY_get_default_digest_nid function returns 1 if the message digest is advisory (that is other digests can be used) and 2 if it is mandatory (other digests cannot be used). It returns 0 or a negative value for failure. In particular, a return value of -2 indicates the operation is not supported by the public key algorithm. .Sh SEE ALSO .Xr EVP_PKEY_asn1_set_ctrl 3 , .Xr EVP_PKEY_CTX_ctrl 3 , .Xr EVP_PKEY_CTX_new 3 , .Xr EVP_PKEY_new 3 , .Xr EVP_PKEY_sign 3 , .Xr EVP_PKEY_verify 3 , .Xr EVP_PKEY_verify_recover 3 .Sh HISTORY .Fn EVP_PKEY_get_default_digest_nid first appeared in OpenSSL 1.0.0 and has been available since .Ox 4.9 .