Weakness of lightweight block ciphers mCrypton and LED against biclique cryptanalysis

Abstract

In this paper, we evaluate the security of lightweight block ciphers mCrypton and LED against biclique cryptanalysis. In cases of mCryton-64/96/128, our attacks require computational complexities of and , respectively. These results are the first known biclique cryptanalytic results on mCrypton. The attack on a 29-round reduced LED-64 needs 29-round reduced LED-64 encryptions. In the cases of LED-80/96/128, we propose the attacks on two versions. First, to recover the secret key of 45-round reduced LED-80/96/128, our attacks require computational complexities of and , respectively. To attack the full version, we require computational complexities of and , respectively. However, in these cases, we need the full codebook. These results are superior to known biclique cryptanalytic results on LED.