Distinguishers for Ciphers and Known Key Attack against Rijndael with Large Blocks

Knudsen and Rijmen introduced the notion of known-key distinguishers in an effort to view block cipher security from an alternative perspective e.g. a block cipher viewed as a primitive underlying some other cryptographic construction such as a hash function; and applied this new concept to construct a 7-round distinguisher for the AES and a 7-round Feistel cipher. In this paper, we give a natural formalization to capture this notion, and present new distinguishers that we then use to construct known-key distinguishers for Rijndael with Large Blocks up to 7 and 8 rounds.