I have some data which I’m encrypting using Aes-Gcm. Every time I have to encrypt the data, I generate a random nonce of the appropriate size, as well as an empty array for the tag data.

In Aes-Gcm, there is an option to provide AAD, or Additional Authenticated Data. To my knowledge, AAD is basically some plaintext data that is authenticated when you decrypt using Gcm.

Normally I believe you just prepend the nonce in plaintext. However, since the nonce is generated before the encryption is called, I was wondering if you could pass in the nonce as the AAD.

Would this be a security risk? Would it help? Or would it not matter at all?