Biclique Cryptanalysis of Full Round AES with Reduced Data Complexity

Abstract. Biclique cryptanalysis was proposed by Bogdanov et al. in Asiacrypt 2011 as a new tool for cryptanalysis of block ciphers. A major hurdle in carrying out biclique cryptanalysis is that it has a very high query complexity (of the order of 2 for AES-128, 2 for AES-192 and 2 for AES-256). This naturally puts a big question mark over the practical feasibility of implementing biclique attack in real world. In this work, we re-evaluate the security of full round AES against biclique cryptanalysis. We describe an alternate biclique construction with signi cantly reduced query complexity (of the order of 2 for AES-128, 2 for AES-192 and 2 for AES-256) at the expense of a slightly increased computational cost. In our approach, we use independent biclique technique to launch a chosen ciphertext attack against AES.