EVP_PKEY_get_default_digest_nid - get default signature digest
#include <openssl/evp.h>
int EVP_PKEY_get_default_digest_nid(EVP_PKEY *pkey, int *pnid);The EVP_PKEY_get_default_digest_nid() function sets pnid to the default message digest NID for the public key signature operations associated with key pkey. Note that some signature algorithms (i.e. Ed25519 and Ed448) do not use a digest during signing. In this case pnid will be set to NID_undef.
For all current standard OpenSSL public key algorithms SHA1 is returned.
The 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 can not 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.
EVP_PKEY_CTX_new(3), EVP_PKEY_sign(3), EVP_PKEY_verify(3), EVP_PKEY_verify_recover(3),
This function was added in OpenSSL 1.0.0.
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Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at https://www.openssl.org/source/license.html.