+New or agile applications should use probably use SHA-256. Other digests,
+particularly SHA-1 and MD5, are still widely used for interoperating
+with existing formats and protocols.
+
+When signing a file, B<dgst> will automatically determine the algorithm
+(RSA, ECC, etc) to use for signing based on the private key's ASN.1 info.
+When verifying signatures, it only handles the RSA, DSA, or ECDSA signature
+itself, not the related data to identify the signer and algorithm used in
+formats such as x.509, CMS, and S/MIME.