+xxx why use this function
+
+=back
+
+=head OTHER FUNCTIONS AND METHODS
+
+=over
+
+=item C<< $verifier_or_authreq->hash($data) >>
+
+Hashes the supplied data using the hash function specified by the
+C<hash_algorithm> setting, and converts the result to a string of hex
+digits.
+
+=item C<< something->update_get_need_add_hidden($reqtype, $value, [$force]) >>
+
+Updates CGI::Auth::Generic's knowledge about the various kinds of
+request, and whether they need the hidden form parameter. This
+function applies only to GET requests - POST requests always use the
+parameter.
+
+I<$reqtype> is the request type (the value which will be passed to
+C<check_nonpage> and C<need_add_hidden>. If you are supporting a new
+I<$reqtype> you shouuld coordinate with CGI::Auth::Flexible upstrea,
+or other users, to assign a unique request type name.
+
+This method may be called on an authreq or a verifier, in which case
+it will affect all authreqs using the same verifier. Or it may be
+called on the class as a whole, in which case it will affect the
+global default list for all verifiers.
+
+If I<$force> is supplied and true, this will override
+CGI::Auth::Flexible's existing knowledge. Otherwise this new setting
+will be ignored if CGI::Auth::Flexible already knows about the request
+type. (When called on a verifier or authreq, it will ignore the
+update in favour of existing knowledge recorded both globally in the
+class or due to previous requests on the same verifier.)
+
+See L</REQUEST TYPES>.
+
+=item C<< $verifier_or_authreq->($data) | CGI::Auth::Flexible->>>
+
+Hashes the supplied data using the hash function specified by the
+C<hash_algorithm> setting, and converts the result to a string of hex
+digits.
+