对MIBS算法的中间相遇攻击

Meet-in-the-middle Attacks on MIBS

MIBS是一种Feistel结构的轻量级分组密码算法,它广泛适用于RFID等计算资源严格受限的环境.评估了简化轮数的MIBS算法对中间相遇攻击的抵抗能力,研究了MIBS算法的一个等价结构,构造出它的一个6轮区分器.基于6轮区分器,利用中间相遇攻击的方法,分别对8/9/10轮的MIBS-64/80和11轮的MIBS-80进行了攻击,并利用密钥生成算法中轮密钥之间的关系降低了数据复杂度和时间复杂度.所有的攻击实例都给出了复杂度分析.攻击结果表明11轮的MIBS-80对中间相遇攻击是不免疫的.

MIBS is a lightweight block cipher of Feistel structure for extremely constrained envi- ronments such as RFID tags. Security of the reduced-round MIBS against meet-in-the-middle attack was evaluated. A 6-round distinguisher of MIBS was constructed through the study of an equivalent structure of MIBS. Based on the 6-round distinguisher,some meet-in-the-middle attacks were made on 8/9/10-round MIBS-64/80 and ll-round MIBS-80. The key scheduling was taken into account and the relations between the round subkeys were exploited in the key recovery process, which re- duced the data and time complexity. A complexity analysis of each attack instance was given. The results demomstrate that reduced-to-ll-rounds MIBS-80 are not immune to meet-in-the-middle at- tack.