Where should I store the IVs for encrypted records?

Question

I'd like to encrypt some secret data before I store them in my database. RijndaelManaged seems a good option for this, but if I understand well, I need to generate a new IV for every single time when I encrypt something. So, where should I store these? Is it a good idea to concatenate the initialization vector and the encrypted value?

Answer 1

The IV is not secret, you can store it anywhere you like. You can certainly store it in front of the ciphertext.

It is a good idea to have an IV, too, although it is optional in some cipher modes. I would use it whenever possible because it mitigates some attacks in certain situations. "Layman" cryptographers like us should play it very safe.