oracle 用sql实现密码的加密，解密

 select utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw('123456'))) from dual;

select utl_raw.cast_to_varchar2(utl_encode.base64_decode(utl_raw.cast_to_raw('MTIzNDU2'))) from dual