1=pod 2 3=head1 NAME 4 5EVP_PKEY_get_default_digest_nid, EVP_PKEY_get_default_digest_name 6- get default signature digest 7 8=head1 SYNOPSIS 9 10 #include <openssl/evp.h> 11 12 int EVP_PKEY_get_default_digest_name(EVP_PKEY *pkey, 13 char *mdname, size_t mdname_sz); 14 int EVP_PKEY_get_default_digest_nid(EVP_PKEY *pkey, int *pnid); 15 16=head1 DESCRIPTION 17 18EVP_PKEY_get_default_digest_name() fills in the default message digest 19name for the public key signature operations associated with key 20I<pkey> into I<mdname>, up to at most I<mdname_sz> bytes including the 21ending NUL byte. The name could be C<"UNDEF">, signifying that a digest 22must (for return value 2) or may (for return value 1) be left unspecified. 23 24EVP_PKEY_get_default_digest_nid() sets I<pnid> to the default message 25digest NID for the public key signature operations associated with key 26I<pkey>. Note that some signature algorithms (i.e. Ed25519 and Ed448) 27do not use a digest during signing. In this case I<pnid> will be set 28to NID_undef. This function is only reliable for legacy keys, which 29are keys with a B<EVP_PKEY_ASN1_METHOD>; these keys have typically 30been loaded from engines, or created with L<EVP_PKEY_assign_RSA(3)> or 31similar. 32 33=head1 NOTES 34 35For all current standard OpenSSL public key algorithms SHA256 is returned. 36 37=head1 RETURN VALUES 38 39EVP_PKEY_get_default_digest_name() and EVP_PKEY_get_default_digest_nid() 40both return 1 if the message digest is advisory (that is other digests 41can be used) and 2 if it is mandatory (other digests can not be used). 42They return 0 or a negative value for failure. In particular a return 43value of -2 indicates the operation is not supported by the public key 44algorithm. 45 46=head1 SEE ALSO 47 48L<EVP_PKEY_CTX_new(3)>, 49L<EVP_PKEY_sign(3)>, 50L<EVP_PKEY_digestsign_supports_digest(3)>, 51L<EVP_PKEY_verify(3)>, 52L<EVP_PKEY_verify_recover(3)>, 53 54=head1 HISTORY 55 56This function was added in OpenSSL 1.0.0. 57 58=head1 COPYRIGHT 59 60Copyright 2006-2023 The OpenSSL Project Authors. All Rights Reserved. 61 62Licensed under the Apache License 2.0 (the "License"). You may not use 63this file except in compliance with the License. You can obtain a copy 64in the file LICENSE in the source distribution or at 65L<https://www.openssl.org/source/license.html>. 66 67=cut 68