Biclique cryptanalysis on lightweight block cipher: HIGHT and Piccolo

Biclique cryptanalysis is an attack that improves the computational complexity by finding a biclique which is a kind of bipartite graph. We present a single-key full-round attack of lightweight block ciphers, HIGHT and Piccolo by using biclique cryptanalysis. In this paper, a 9-round biclique is constructed for HIGHT and a 4-round biclique for Piccolo. These new bicliques are used to recover secret keys for the full rounds of HIGHT, Piccolo-80 and Piccolo-128, the computational complexity of 2125.93, 279.34 and 2127.36, respectively. The computational complexity of attacking HIGHT by a biclique cryptanalysis is reduced from 2126.4. This is the first full-round attack on both Piccolo-80 and Piccolo-128.