12 hours ago
- Mythos improved AES-7 attack efficiency by 200-800x by discovering a byte that only permutes output, reducing 256x computation via invariant fingerprint.
- The fingerprint algorithm eliminates looping over one guessed key byte, cutting checks from 256^3 to 256^2, then a final 256 checks to verify.
- The insight simplifies attack expression to Table[index xor guessed_key_byte], showing the guess merely shifts table lookup.
- This speedup applies only to 7-round AES, not the 10-round version, and cost ~$100k in API tokens over a week.
- Verification of the attack took two researchers a month; prompts used were conversational, treating AI like a human.