View Full Version : AES exchanging IVs

09-10-2008, 02:52 PM
If I want to encrypt and later decrypt something with AES (CBC mode) I need to have a key and an initial vector (IV).

I can keep the key secret (it is only me that will be encrypting and decrypting) as much as I could keep a private key secret in asymmetric encryption. The problem is the IV. Should I use the same IV every time (that really can't be a good idea) or should I put the IV in with the encrypted data (that also can't be a very good idea).

The only other alternative I can think of is using asymmetric encryption for the IV so that only I can decrypt it.

What is the normal approach to this?