safety – Can the iv used in AES-CTR be stored in clear?

Question:

I plan to use the AES cipher in counter mode and I'm not sure if I can keep the iv (nonce + counter) in clear.

Answer:

A Wikipedia article says (the translation is mine):

An initialization vector has different security requirements than a key, so the IV need not be secret. However, in most cases it is important that the initialization vector is never reused with the same key.

You don't need to keep the iv a secret, but you do have to make sure it's unique.

Scroll to Top