关键词: MD5，差分控制，Hash函数，解析

Abstract: This paper is about the cryptanalysis of the Hash function MD5，on the basis of the paper concerning the breaking the MD5 which was written by Wang et al. In this paper, the eighth step of MD5 algorithm was taken for example and the properties of the F function and the effective control of the differential path were introduced. The MD5 algorithm was cryptanalyzed from both the manual calculation and the testing program and some part of the paper written by Wang was amended. Finally, the conditions and key points of meeting the differential characteristics were discussed. In general, this paper plays an important role in cryptanalyzing and breaking the MD5 algorithm.

Key words: MD5,Differential control,Hash function, Cryptanalysis