+L<gendsa(1)|gendsa(1)>, L<verify(1)|verify(1)>,
+L<x509v3_config(5)|x509v3_config(5)>
+
+=head1 HISTORY
+
+Before OpenSSL 0.9.8, the default digest for RSA keys was MD5.
+
+The hash algorithm used in the B<-subject_hash> and B<-issuer_hash> options
+before OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encoding
+of the distinguished name. In OpenSSL 1.0.0 and later it is based on a
+canonical version of the DN using SHA1. This means that any directories using
+the old form must have their links rebuilt using B<c_rehash> or similar.