Known-Key Distinguishers for Some Block Ciphers

Abstract

We present two block cipher distinguishers in a setting where the attacker knows the key. One is a distinguisher for AES reduced the seven rounds. The second is a distinguisher for a class of Feistel ciphers with seven rounds. This setting is quite different from traditional settings. We present an open problem: the definition of a new notion of security that covers attacks like the ones we present here, but not more.