I'm actually not sure, I would need to look at it again. As you said, AES-128 is probably the most sound in a theoretical sense, but AES-256 stronger against br

I'm actually not sure, I would need to look at it again. As you said, AES-128 is probably the most sound in a theoretical sense, but AES-256 stronger against brute force and that makes up for the theoretical problems. AES-192 is a weird middle option that's less strong against brute force than AES-256, and is also theoretically less sound that AES-128.