Biclique Attack on Block Cipher LBlock with Low Data Complexity

LBlock is a Lightweight block cipher, with a 64-bit block size and 80-bit key length. Biclique attack is a kind of MITM attack that has recently attracted lots of attention. Biclique cryptanalysis often breaks full version of the cipher on which many other existing attacks do not work. In this paper, firstly, asymmetric biclique is introduced, then by using low data complexity algorithm technique (LDC), a biclique attack on full round Lightweight block cipher LBlock is presented. The computation and data complexity of this attack are and, respectively. The data complexity is considerably less than the existing cryptanalytic result. The computational complexity remains the same as the previous ones.