How to protect sensitive data from database?

[neelesh kumar]

I am building a small application which stores all the confidential data like bank account no., credit card no., etc of the user...I planned on using the transparent data encryption (TDE) provided by oracle...however the problem is that if I use it, the data can still be accessed by the database administrator which is not desired. What should be done? I read somewhere that application level encryption will solve this problem...I am not sure what that is.

[Ulf Dittmer]

It means the application code would encrypt the data before it gets stored in the DB, and then decrypt it when it gets it out of the DB. The key would be in the app code (or maybe not even that, maybe part of it would need to be entered by the user, so that even if the code got compromised, the data could still not get decrypted).

I have to say, though - if you see the DB admins as a source of problems, you probably got bigger issues to worry about.

[Martin Vashko]

Furthermore, Oracle does have mechanisms to protect sensitive data even from admins. There are different levels of admin privileges to start with (even a backup operator doesn't need to know the encryption key, for example), and also the password can be split among two (don't know if not even more) persons, so that they would have to work in tandem to get to the data (see http://www.oracle.com/technetwork/database/security/twp-transparent-data-encryption-bes-130696.pdf).

I'd suggest to read Oracle's documentation on the subject. Though you'll have to spend good amount of time to read all of them, I strongly believe that you'd need to invest much more time to get solution which would be safer than the one Oracle already has.

[neelesh kumar]

Using an application level encryption makes sense. Can someone tell me how to implement it? What if I build a Java applet that carries out the process of encryption and decryption on its own? In this way the admin can never know the data in the database since the data will be stored in an encrypted form which he cannot decrpyt., and the user too wont have to worry about decryption since it will automatically be done at client's side by the applet.....

Is this possible? How can it be done?

[Ulf Dittmer]

Ugh... applets are too outdated and insecure to deploy these days. What's more, putting encryption keys into the applet makes them vulnerable to decompilation.

[neelesh kumar]

Is there any tutorial to implement application level encryption? Will be a great help!

[Ulf Dittmer]

Not sure what you're looking for - you encrypt data before storing it in the DB, and decrypt it after retrieving it. There isn't much to it but a knowledge of encryption in general.

If you've never used JCE -the standard Java API for encryption- start here: https://coderanch.com/how-to/java/SecurityFaq#encryption