DH算法是W.Diffie和M.Hellman提出的。此算法是最早的公钥算法。它实质是一个通信双方进行密钥协定的协议：两个实体中的任何一个使用自己的私钥和另一实体的公钥，得到一个对称密钥，这一对称密钥其它实体都计算不出来。-DH algorithm is W. Diffie and M. Hellman proposed. This algorithm is one of the first public key algorithm. It is essentially a communication two key agreements: the two entities in any one to use their own private key and another entity