AES256 bit encyption key from 64 character long string

Question

Hi,
I have Oracle 10.2 on Windows 2003. I have recently started working on a project that requires encrypting information before sending it over. I have got 64 character long string to use it as a key.
I am getting ORA-06502: PL/SQL: numeric or value error: raw variable length too long
<pre>
declare
input_string VARCHAR2 (200) := 'SomeText';
output_string VARCHAR2 (200);
encrypted_raw RAW (2000); -- stores encrypted binary text
decrypted_raw RAW (2000); -- stores decrypted binary text
key_bytes_raw RAW (32); -- stores 256-bit encryption key
encryption_type PLS_INTEGER; -- total encryption type
begin
DBMS_OUTPUT.PUT_LINE ('Original string: ' || input_string);
encryption_type := DBMS_CRYPTO.ENCRYPT_AES256 + DBMS_CRYPTO.CHAIN_CBC + DBMS_CRYPTO.PAD_PKCS5;
key_bytes_raw := UTL_I18N.STRING_TO_RAW('eiccmkjd94jfgniw03ljkdlfutcnv3209kfjd67023jlclmxzlmc9543ykflseu6', 'AL32UTF8');
encrypted_raw := DBMS_CRYPTO.ENCRYPT
src => UTL_I18N.STRING_TO_RAW (input_string, 'AL32UTF8'),
typ => encryption_type,
key => key_bytes_raw
-- The encrypted value in the encrypted_raw variable can be used here
decrypted_raw := DBMS_CRYPTO.DECRYPT
src => encrypted_raw,
typ => encryption_type,
key => key_bytes_raw
output_string := UTL_I18N.RAW_TO_CHAR (decrypted_raw, 'AL32UTF8');
DBMS_OUTPUT.PUT_LINE ('Decrypted string: ' || output_string);
end;
Please let me know hot to convert 64 character long string in to 256bit key.
Thanks
-Smith

Answer 1

smith_apex wrote:
My client is using Java and they are saying that they are using this key for their AES256 Encryption and working fine. I have asked them to provide me 32 bytes key as in Oracle 256bit is 32 character string.
Let me see what they have to say.
I was wondering why Java has 64 bytes for 256 AES encryption when Oracle need only 32 bytes for same encryption.I am not sure I completely understand how those built-in packages work but the doc example produces the raw key that is same in length (in terms of number of characters) as the one you are using.
Yet your UTL_I18N packaged function fails for your key but works for the documentation example.
Documentation example:
SQL> select * from v$version ;
BANNER
Oracle Database 10g Release 10.2.0.5.0 - Production
PL/SQL Release 10.2.0.5.0 - Production
CORE     10.2.0.5.0     Production
TNS for Linux: Version 10.2.0.5.0 - Production
NLSRTL Version 10.2.0.5.0 - Production
declare
   input_string       VARCHAR2 (200) := 'Secret Message';
   output_string      VARCHAR2 (200);
   encrypted_raw      RAW (2000);             -- stores encrypted binary text
   decrypted_raw      RAW (2000);             -- stores decrypted binary text
   num_key_bytes      NUMBER := 256/8;        -- key length 256 bits (32 bytes)
   key_bytes_raw      RAW (32);               -- stores 256-bit encryption key
   encryption_type    PLS_INTEGER :=          -- total encryption type
                            DBMS_CRYPTO.ENCRYPT_AES256
                          + DBMS_CRYPTO.CHAIN_CBC
                          + DBMS_CRYPTO.PAD_PKCS5;
begin
   DBMS_OUTPUT.PUT_LINE ('Original string: ' || input_string);
   DBMS_OUTPUT.PUT_LINE ('Encryption Type: ' || encryption_type);
   key_bytes_raw := DBMS_CRYPTO.RANDOMBYTES (num_key_bytes);
   DBMS_OUTPUT.PUT_LINE ('Key Bytes(RAW): ' || key_bytes_raw);
   encrypted_raw := DBMS_CRYPTO.ENCRYPT
         src => UTL_I18N.STRING_TO_RAW (input_string, 'AL32UTF8'),
         typ => encryption_type,
         key => key_bytes_raw
   DBMS_OUTPUT.PUT_LINE ('Encrypted string: ' || encrypted_raw);
    -- The encrypted value in the encrypted_raw variable can be used here
   decrypted_raw := DBMS_CRYPTO.DECRYPT
         src => encrypted_raw,
         typ => encryption_type,
         key => key_bytes_raw
   output_string := UTL_I18N.RAW_TO_CHAR (decrypted_raw, 'AL32UTF8');
   DBMS_OUTPUT.PUT_LINE ('Decrypted string: ' || output_string);
end;
32   33   34  /
Original string: Secret Message
Encryption Type: 4360
Key Bytes(RAW): 52EC66508FDF1E5DE5FD38EC2467FAA91009B738A2926AA870E142C080C72EBF
Encrypted string: 0BDDC2B94F7044700D85624297A39025
Decrypted string: Secret Message
PL/SQL procedure successfully completed.
SQL> select length('52EC66508FDF1E5DE5FD38EC2467FAA91009B738A2926AA870E142C080C72EBF') from dual ;
LENGTH('52EC66508FDF1E5DE5FD38EC2467FAA91009B738A2926AA870E142C080C72EBF')
                                             64
SQL> select dump('52EC66508FDF1E5DE5FD38EC2467FAA91009B738A2926AA870E142C080C72EBF') from dual ;
DUMP('52EC66508FDF1E5DE5FD38EC2467FAA91009B738A2926AA870E142C080C72EBF')
Typ=96 Len=64: 53,50,69,67,54,54,53,48,56,70,68,70,49,69,53,68,69,53,70,68,51,56,69,67,50,52,54,55,70,65,65,57,49,48,48,57,66,55,51,56,65,50,57,50,54,65,65,56,55,48,69,49,
52,50,67,48,56,48,67,55,50,69,66,70Your example:
declare
   input_string       VARCHAR2 (200) := 'SomeText';
   output_string      VARCHAR2 (200);
   encrypted_raw      RAW (2000);             -- stores encrypted binary text
   decrypted_raw      RAW (2000);             -- stores decrypted binary text
   key_bytes_raw      RAW (32);               -- stores 256-bit encryption key
   encryption_type    PLS_INTEGER;          -- total encryption type
begin
   DBMS_OUTPUT.PUT_LINE ('Original string: ' || input_string);
   encryption_type :=   DBMS_CRYPTO.ENCRYPT_AES256 + DBMS_CRYPTO.CHAIN_CBC + DBMS_CRYPTO.PAD_PKCS5;
   key_bytes_raw := UTL_I18N.STRING_TO_RAW('eiccmkjd94jfgniw03ljkdlfutcnv3209kfjd67023jlclmxzlmc9543ykflseu6', 'AL32UTF8');
   DBMS_OUTPUT.PUT_LINE ('Key Bytes(RAW): ' || key_bytes_raw);
   encrypted_raw := DBMS_CRYPTO.ENCRYPT
         src => UTL_I18N.STRING_TO_RAW (input_string, 'AL32UTF8'),
         typ => encryption_type,
         key => key_bytes_raw
    -- The encrypted value in the encrypted_raw variable can be used here
   decrypted_raw := DBMS_CRYPTO.DECRYPT
         src => encrypted_raw,
         typ => encryption_type,
         key => key_bytes_raw
   output_string := UTL_I18N.RAW_TO_CHAR (decrypted_raw, 'AL32UTF8');
   DBMS_OUTPUT.PUT_LINE ('Decrypted string: ' || output_string);
end;
27   28   29   30  /
Original string: SomeText
declare
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: raw variable length too long
ORA-06512: at line 12
SQL> select length('eiccmkjd94jfgniw03ljkdlfutcnv3209kfjd67023jlclmxzlmc9543ykflseu6') from dual ;
LENGTH('EICCMKJD94JFGNIW03LJKDLFUTCNV3209KFJD67023JLCLMXZLMC9543YKFLSEU6')
                                             64
SQL> select dump('eiccmkjd94jfgniw03ljkdlfutcnv3209kfjd67023jlclmxzlmc9543ykflseu6') from dual ;
DUMP('EICCMKJD94JFGNIW03LJKDLFUTCNV3209KFJD67023JLCLMXZLMC9543YKFLSEU6')
Typ=96 Len=64: 101,105,99,99,109,107,106,100,57,52,106,102,103,110,105,119,48,51,108,106,107,100,108,102,117,116,99,110,118,51,50,48,57,107,102,106,100,54,55,48,50,51,106,
108,99,108,109,120,122,108,109,99,57,53,52,51,121,107,102,108,115,101,117,54