def _compute_http_digest_a1(self, realm, user_name, password):
data = user_name + "<STR_LIT::>" + realm + "<STR_LIT::>" + password<EOL>A1 = md5(compat.to_bytes(data)).hexdigest()<EOL>return A1<EOL>
Internal helper for derived classes to compute a digest hash (A1 part).