关键词: MD5 强度分析 哈希函数 碰撞

Abstract:

Analyzing the resistibility of the MD5 algorithm, this paper tries to give some advice and prediction on how to improve Hash functions.As a widely used Hash function, an iteration of the MD5 algorithm includes 4 rounds, 64 steps and one addition.Through the analyses from steps to rounds, and from rounds to iterations, the authors give the break points of recent research and how to overcome them. Based on the recent research in the Hash world, the authors ameliorate the conclusions of reference 1,make the probability analysis of reference 1confirmable with the ameliorated conclusions,give the biggest k of the k-preimage attack of Wang-like collisions,and give four directions and advice on how to improve Hash functions at the end of this paper.

Key words: MD5;resistibility analysis;Hash function;collision