Mod n Cryptanalysis, with Applications Against RC5P and M6

We introduce “mod n cryptanalysis,” a form of partitioning attack that is effective against ciphers which rely on modular addition and bit rotations for their security. We demonstrate this attack with a mod 3 attack against RC5P, an RC5 variant that uses addition instead of xor. We also show mod 5 and mod 257 attacks against some versions of a family of ciphers used in the FireWire standard. We expect mod n cryptanalysis to be applicable to many other ciphers, and that the general attack is extensible to other values of n.

• Type: Conference
• Year: 1999
• Where: FSE
• Authors: John Kelsey, Bruce Schneier, David Wagner
• Keywords: Bit Rotations, Cryptology, FSE 1999, Mod 257 Attacks, Modular Addition