A Real-Time Attack on the GMR-2 Encryption Algorithm in Satellite Phones

摘要

In this paper, we present one meth-od to attack on the GMR-2 algorithm used in satellite phone under the chosen-plaintexts. First using the relationship of the rows of the two s-boxes and outputs of the F coordinate, we attack on the GMR-2 algorithm. Then we deduce the happening probability of read-col-lision, and analyze its mathematical expecta-tion. Finally, combining with the read-colli-sion, we present an improved method to attack on the GMR-2 algorithm. The research results show that the complexity of the improved al-gorithm is about 220, and the session key Kc can be recovered in about 0.3 seconds. Com-pared with the available method, our method takes less time than the guess-and-decide at-tack method which is 700s.