Md5

MD5, or Message-Digest Algorithm 5 (Information-Summary algorithm 5), is used to ensure that the transmission of information is complete and consistent. It is one of the hash algorithms (abstract algorithm and hash algorithm) widely used in computers. MD5 has been implemented in mainstream programming languages. Computing data (such as Chinese characters) into another fixed length value is the basic principle of hash algorithm. The predecessor of MD5 is MD2, MD3 and MD4.

The md5 hash is typically a 32-bit hexadecimal number.

MD5 algorithm has the following characteristics:

1. Compressibility: any length of data, the calculated MD5 value length is fixed, 32-bit length.

2. Easy to calculate: it is easy to calculate the MD5 value from the original data.

3. Anti-modification: if you make any changes to the original data, even if you only modify 1 byte, the MD5 values obtained are very different.

4. Strong anti-collision: knowing the original data and its MD5 value, it is very difficult to find a data with the same MD5 value (that is, forged data).

The concrete realization process of MD5 algorithm.

Http://baike.baidu.com/view/7636.htm