Related key attacks on reduced round kasumi

Abstract

This paper describes related key attacks on five and six round KASUMI. The five round attack requires the encryption of approximately 219 chosen plaintext pairs X and X ∗ under keys K and K ∗ respectively where K and K ∗ differ in only one bit, and requires a maximum of a little over 233 trials to recover the entire key. The sixround attack requires a smaller number of chosen plaintext encryptions than the five round attack, and recovers the entire key in a maximum of 2112 trials.