主题：【文摘】山东大学王小云教授成功破解MD5 -- 懒厨

首先说一下MD5是个什么东西，比较常见的定义是：

MD5 was developed by Professor Ronald L. Rivest of MIT. The MD5 algorithm takes as input a message of arbitrary length and produces as output a 128-bit "fingerprint" or "message digest" of the input. It is conjectured that it is computationally infeasible to produce two messages having the same message digest, or to produce any message having a given prespecified target message digest. The MD5 algorithm is intended for digital signature applications, where a large file must be "compressed" in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA.

In essence, MD5 is a way to verify data integrity, and is much more reliable than checksum and many other commonly used methods.

是不是MD5一旦有了破解，整个世界就开始动摇了呢？我感觉不是。因为MD5只是非对称加密中的一个环节，对于非对称加密的安全性有多大危害还不清楚。对于加密的另外一大分支--对称加密似乎没有什么影响。比如对于现在美国NIST推荐的AES(Advanced Encryption Standard)加密技术就没有什么威胁.

The Advanced Encryption Standard (AES) is a National Institute of Standards and Technology specification for the encryption of electronic data. It is expected to become the accepted means of encrypting digital information, including financial, telecommunications, and government data.