MD5碰撞攻击的多重消息修改技术的研究

Research on the multi-message modification techniques on MD5

通过对王小云等提出的消息修改技术以及YuSasaki等提出改进的消息修改技术进行研究,指出他们提出的多重消息修改技术并不总能使一个链接变量同时满足多个充分条件,并给出了确保一个链接变量同时满足多个充分条件的方法。此外还指出了在LiangJie和LaiXuejia的新的充分条件集中YuSasaki等的改进的多重消息修改技术对其中2个条件不能再实施,并提出了对其中一个新的消息修改技术,给出了对另外3个充分条件的新的多重消息修改技术,并通过实验对上述结果进行了验证且产生了新的MD5碰撞对。

According to research on the message modification techniques presented by Wang Xiaoyun et al and the ad- vanced message modification techniques proposed by Yu Sasaki et al, the multi-message modification techniques were founded to not be always able to make a chaining value satisfy several sufficient conditions simultaneously and with it a method was presented to make it up. Moreover, two of the sufficient conditions were pointed out since they are no longer able to be modified by the method presented by Yu Sasaki et al in the new set of sufficient conditions proposed by Liang Jie and Lai Xuejia, and a new method was proposed to make one of them satisfied deterministically. Additionally, new multi-message modification techniques were presented to modify the other three sufficient conditions. Finally, the results are tested by computer simulations and produce new collision pairs for MD5.