Oracle 创建md5函数

CREATE OR REPLACE FUNCTION MD5(passwd IN VARCHAR2)RETURN VARCHAR2
IS
    retval varchar2(32);
BEGIN
  if passwd is not null then
    retval := utl_raw.cast_to_raw(DBMS_OBFUSCATION_TOOLKIT.MD5(INPUT_STRING => passwd)) ;
  else 
    RETURN passwd;
    end if;
RETURN retval;
END;