Encrypting NULL

Question

While using Javax.crypto ciphers (more specific AES128/CBC/PKCS5Padding), the doFinal throws a NullPointerException when passing null to it as method args.

Is there a way to encrypt null so that when persisting it to the database, I don't store null as null or something similar?

I guess the method expects an actual object and not "nothing"... — SEJPM, Feb 21 '17 at 11:01
Would encrypting a zero-length byte array satisfy your requirement? or do you need to distinguish between empty and null? — user207421, Feb 22 '17 at 05:51

score 4 · Answer 1 · answered Feb 21 '17 at 11:46

No, you can't encrypt NULL... encryption requires an input value (which NULL is not). If you absolutely must store an encrypted value in your database, you could check whether the value being encrypted is NULL and cast it to an representative value (empty string, 0, whatever your preference), and upon decryption perform a similar check for that value, and recast back to NULL. However, in my opinion, this is hacky and should be avoided - it's better not to store any value at all, but I don't know your circumstances.

score 0 · Answer 2 · answered Feb 22 '17 at 05:50

0

Check for null before attempting to encrypt. If it's null, don't encrypt it. Likewise for decryption.

answered Feb 22 '17 at 05:50

Maybe_Factor

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This does not satisfy 'when persisting it to the database, I don't store `null` as `null`'. – user207421 Feb 22 '17 at 06:05
That's a good point, EJP. I'd advise the OP to reconsider not storing nulls as null in the database. – Maybe_Factor Feb 22 '17 at 22:55
Well that may not satisfy his requirement either. He may have a requirement to hide whether a column is null. – user207421 Feb 22 '17 at 23:00
Yes, turns out it's quite difficult to meet requirements if you don't know what the requirements are. – Maybe_Factor Feb 23 '17 at 00:02

Encrypting NULL

2 Answers2