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I want to encrypt a field in a table (it contains credit card number).
I tried to do it using dbms_obfuscation_toolkit, but the problem is encrypted string becomes much larger in length compared to actual field length (16 characters).
How can I encrypt the field to keep it same length yet hard to break?
Thanks a lot in advance.
I've a sneeking suspicion that it might be impossible - in some naïve way I expect the encrypted string to hold more information than the plain text - it includes some knowledge about the password too - so it must be longer. Is anyone out there up on information theory?
Vague ideas for solving your problem:
- map your number onto a shorter text string: two digits could map into one character using CHR(nn). How big is a CHAR(8) when encrypted?
- can you avoid encrypting the first x digits? AFAIK, they only indicate the card type (VISA, AmEx etc).
- what are the possibilties for encrypting it as an integer rather than text?
Thanks.
No, I can't discard some fields. It can store either 16 or 18 digits in the field. Also, encrypting it to an integer is difficult. Oracle's obfuscation toolkit is a standard package. Now, if I use any logic of my own the client may not approve it!
What DaPI means is to convert the credit card number to integer (or packed decimal) before encrypting.Quote:
Originally posted by sbasak1
Thanks.
No, I can't discard some fields. It can store either 16 or 18 digits in the field. Also, encrypting it to an integer is difficult. Oracle's obfuscation toolkit is a standard package. Now, if I use any logic of my own the client may not approve it!
Also, to hold encrypted data may require use of a RAW type column. Varchar2 may be used, but you may experience problems with NLS/character conversion when exp/imp data or copying data to another DB.
:D