create or replace package test_md5 as
  function fn_getmd5(p_str in varchar2)
    return varchar2;
  function fn_checkuser(p_username in varchar2,p_password in varchar2)
    return number;
end;
create or replace package body test_md5 as
  function fn_getmd5(p_str in varchar2)
    return varchar2 as
  begin
    return DBMS_OBFUSCATION_TOOLKIT.MD5(
      input_string => Upper(p_str)
    );
  end;
  function fn_checkuser(p_username in varchar2,p_password in varchar2)
    return number
  is
    l_password varchar(1000);
  begin
    select password into l_password from test_user
    where upper(username)=upper(p_username) and password=Test_MD5.FN_GetMD5(p_password);
    if l_password is null Then
      return 0;
    else
      return 1;
    end if;
    exception
    when NO_DATA_FOUND then
      return 3;
  end;
end;

Delete Test_User;
Insert Into Test_User Values('A',Test_MD5.FN_GetMD5('aa'));
Insert Into Test_User Values('B',Test_MD5.FN_GetMD5('bb'));
select * from test_user;
Select Test_MD5.FN_CheckUser('a','aa') From Dual;
Select Test_MD5.FN_CheckUser('a','bb') From Dual;
select * from Test_User t where t.password=test_md5.fn_getmd5('aa')