A Combinatorial Analysis of HC-128.
Goutam Paul, Subhamoy Maitra, Shashwat Raizada · 2010
Abstract. We show that the knowledge of any one of the two internal state arrays of HC-128 along with the knowledge of 2048 keystream words is sufficient to construct the other state array completely in 2 42 time complexity. Though our analysis does not lead to any attack on HC-128, it reveals a structural insight into the cipher. In the process, we theoretically establish certain combinatorial properties of HC-128 keystream generation algorithm. We also suggest a modification to HC-128 that takes care of the recently known cryptanalytic results with little reduction in speed.