Oracle MD5加密

create or replace function FUN_GET_MD5_UPDATE(input_string in varchar2)
  return varchar2
  is
  retval varchar2(100);
BEGIN
  IF INPUT_STRING IS NULL THEN RETURN NULL;
  ELSIF LENGTHB(TRIM(INPUT_STRING))> 18 THEN RETURN INPUT_STRING;
  ELSE

     retval:=dbms_obfuscation_toolkit.MD5(input => utl_raw.cast_to_raw(input_string));
     return lower(rawtohex(retval));
  END IF;
end;