.\"	$OpenBSD: EVP_PKEY_get_default_digest_nid.3,v 1.5 2019/06/06 01:06:58 schwarze Exp $
.\"	OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
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.Dd $Mdocdate: June 6 2019 $
.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
.Fa pnid
to the default message digest NID for the public key signature
operations associated with key
.Fa pkey .
.Pp
For all current standard OpenSSL public key algorithms, SHA1 is returned.
.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 .