对MIBS算法的Integral攻击

Integral Cryptanalysis of Reduced-round MIBS Block Cipher

MIBS是M.Izadi等人在2009开发研制的轻量级分组密码算法,它广泛用于电子标签和传感器网络等环境.本文给出了对MIBS算法Integral攻击的4.5轮区分器,利用该区分器对MIBS算法进行了8轮和9轮的Integral攻击,并利用密钥编排算法中轮密钥之间的关系,结合"部分和"技术降低了攻击的时间复杂度.攻击结果如下:攻击8轮MIBS-64的数据复杂度和时间复杂度分别为238.6和224.2;攻击9轮MIBS-80的数据复杂度和时间复杂度分别为239.6和268.4.本文攻击的数据复杂度和时间复杂度都优于穷举攻击.这是对MIBS算法第一个公开的Integral攻击.

MlBS is a lightweight block cipher with 64-bit block length and 64/80-bit key length, which was designed by M. Izadi et al in 2009 for extremely constrained environments such as RFID tags and sensor networks. In this paper we find some 4.5-round integral distinguishers of MIBS which may lead to integral attacks on 8-round MIBS-64 and 9-round MIBS-80. We take the key schedu- ling algorithm into account, and exploit the relations between the round subkeys, together with partial sum technique in the key recovery process to reduce the computational workload. The data and time complexities of 8-round attack on MIBS-64 are 2^38.6 and 2^24.2 respectively. The data and time complexities of 9-round attack on MIBS- 80 are 2^39.6 and 2^68.4 respectively. The results of the attacks are better than exhaustive search. This is the first published integral cryptanalysis on MIBS block cipher.