Zero-correlation linear attack is a new method for cryptanalysis of block ciphers developed by Bogdanov et al. in 2012. In this paper we adapt the matrix method to find zerocorrelation linear approximations. Then we present several zero-correlation linear approximations for 14 rounds of LBlock and describe a cryptanalysis for 22 rounds of the reduced LBlock. After biclique attacks on LBlock rev...

We present a new concept of biclique as a tool for preimage attacks, which employs many powerful techniques from differential cryptanalysis of block ciphers and hash functions. The new tool has proved to be widely applicable by inspiring many authors to publish new results of the full versions of AES, KASUMI, IDEA, and Square. In this paper, we show how our concept leads to the first cryptanaly...

Abstract. In this paper, we evaluate the security of lightweight block ciphers PRESENT, Piccolo and LED against biclique cryptanalysis. To recover the secret key of PRESENT-80/128, our attacks require 2 full PRESENT-80 encryptions and 2 full PRESENT-128 encryptions, respectively. Our attacks on Piccolo-80/128 require computational complexities of 2 and 2, respectively. The attack on a 29-round ...

In this paper we introduce Janus, a software framework – written in Java – which is built to provide assistance in finding independent-biclique attacks for a user-chosen set of parameters, e.g., the number of rounds and dimension of the biclique. Given a certain cipher, Janus not only finds an optimal bipartite graph (biclique), but also provides an all-round carefree package of finding an opti...

SQUARE, an 8-round substitution-permutation block cipher, is considered as the predecessor of the AES. In this paper, inspired from the recent biclique attack on the AES [5], we present the first single-key attack on full SQUARE. First, we introduce a biclique for 3 rounds of SQUARE using the independent related-key differentials. Then, we present an attack on the full round of this cipher with...

Since Rijndael was chosen as the Advanced Encryption Standard (AES), improving upon 7-round attacks on the 128-bit key variant (out of 10 rounds) or upon 8-round attacks on the 192/256-bit key variants (out of 12/14 rounds) has been one of the most difficult challenges in the cryptanalysis of block ciphers for more than a decade. In this paper, we present the novel technique of block cipher cry...