urn value 2) or may (for return value 1) be left unspecified.</p>

<p>EVP_PKEY_get_default_digest_nid() sets <i>pnid</i> to the default message digest NID for the public key signature operations associated with key <i>pkey</i>. Note that some signature algorithms (i.e. Ed25519 and Ed448) do not use a digest during signing. In this case <i>pnid</i> will be set to NID_undef. This function is only reliable for legacy keys, which are keys with a <b>EVP_PKEY_ASN1_METHOD</b>; these keys have typically been loaded