Suppose one uses AES in CTR mode to generate a keystream, but every $l$ bytes the $n$ bits that would follow are used as a new AES key.
Assuming that AES is a secure PRP:
- Is this a secure stream cipher?
- How does it compare to standard AES-CTR?
- Suppose the (original) key is mixed back in at each rekeying useing a one-way pseudorandom compression: what changes?
Note that AES is used as an example secure block cipher.