Impossible Differential Attacks on Reduced-Round LBlock
LBlock is a lightweight block cipher with 32 rounds, which can be implemented efficiently not only in hardware environment but also in software platforms. In this paper, by exploiting the structure of LBlock and the redundancy in its key schedule, we propose an impossible differential attack on 21-round LBlock based on a 14-round impossible differential. The data and time complexities are about 262.5 chosen plaintexts and 273.7 21-round encryptions, respectively. As far as we know, these results are the currently best results on LBlock in the single key scenario.
KeywordsBlock Cipher LBlock Impossible Differential Attacks
Unable to display preview. Download preview PDF.
- 1.Biham, E., Biryukov, A., Shamir, A.: Cryptanalysis of Skipjack Reduced to 31 Rounds Using Impossible Differentials. In: Stern, J. (ed.) EUROCRYPT 1999. LNCS, vol. 1592, pp. 12–23. Springer, Heidelberg (1999)Google Scholar
- 2.Biham, E., Shamir, A.: Differential Cryptanalysis of DES-like Cryptosystems. In: Menezes, A., Vanstone, S.A. (eds.) CRYPTO 1990. LNCS, vol. 537, pp. 2–21. Springer, Heidelberg (1991)Google Scholar
- 9.Knudsen, L.R.: DEAL - a 128-bit block cipher. Tech. rep., Department of Informatics, University of Bergen, Norway, technical report (1998)Google Scholar
- 15.Minier, M., Naya-Plasencia, M.: Some preliminary studies on the differential behavior of the lightweight block cipher LBlock. In: Leander, G., Standaert, F.X. (eds.) ECRYPT Workshop on Lightweight Cryptography, pp. 35–48 (November 2011)Google Scholar