Yeah, it's a trick that's been around for a while. The thing that makes it a little fiddly is that the various ways to store a key schedule, especially for decryption - it could be in either order, and there's some optimization to do with whether InvMixColumn is pre-applied to the values that I can't remember the details of. I actually had a fork of the classic aeskeyfind that added some of these tricks, though apparently it's broken at higher compiler optimizations now and I probably need to look into that: https://github.com/makomk/aeskeyfind Could just have used this instead if I'd known about it.