MD5 Encryption on UTF8 database on NVARCHAR datatype column

Question

DECLARE
l_string NVARCHAR2(600) := '123456';
checksum NVARCHAR2(600);
BEGIN
DBMS_OUTPUT.DISABLE;
DBMS_OUTPUT.ENABLE(1000000);
DBMS_OBFUSCATION_TOOLKIT.md5 (input_string => l_string, checksum_string => checksum);
DBMS_OUTPUT.PUT_LINE(RAWTONHEX(utl_raw.cast_to_raw(checksum)));
END;
Expected value: e10adc3949ba59abbe56e057f20f883e
But it returns: FFFD00390049FFFD0059FFFDFFFD0056FFFD000FFFFD003E
Note I want to maintain nvarchar2 datatype. The value from checksum variable gets stored in column that is of type nvarchar2.
I am aware that md5 accepts and returns data in varchar2. But if someone can help me figure this out using nvarchar2 data type, that would be great.
The NLS_CHARACTERSET = AL32UTF8

Answer 1

Welcome to the forums. I agree with Prabodh that the APEX group may not be an idea location to ask this question. Because you are doing things with DBMS_OBFUSCATION_TOOLKIT I'd even try those types of questions in the "Database Security - General" forum which is even more specialized than the SQL/PLSQL group in this regard.
Your question is off to a great start with an easily reproducible test case. You are probably better off with DBMS_CRYPTO which is available in 10g. It's newer, bigger, better and most likely has better support for needs. I did a quick test:
SQL> l
  1  declare
  2  l_string varchar2(600) := '123456';
  3  checksum   nvarchar2(600);
  4  l_hashlower   nvarchar2(600);
  5
  6  begin
  7
  8   checksum := dbms_crypto.hash (utl_raw.cast_to_raw(l_string),2); -- 2 is md5
  9   l_hashlower := lower(rawtohex(checksum));
10
11    dbms_output.put_line('md5hash: ' || checksum);
12    dbms_output.put_line('md5hash-lower: ' || l_hashlower);
13
14* end;
SQL> /
md5hash: E10ADC3949BA59ABBE56E057F20F883E
md5hash-lower: e10adc3949ba59abbe56e057f20f883e
PL/SQL procedure successfully completed.Good luck.