1,2 密码分析 在这一节,我们讨论一些密码分析技术,通常假设敌人Oscar知道正在使用的密码体制,这个假设通常称为Kerckhoff原则。当然如果Oscar不知道正在使用的密码体制,那么他将更困难地完成这个密码分析。但我们并不打算使密码体制的安全性建筑在Oscar不知道正在使用的密码体制这样一种(可能不确定)的假定上。因此我们的目标是设计一个在Kerckhoft原则下安全的密码体制 1, 2 Cryptanalysis In this section, we discuss some cryptanalysis techniques, usually assuming that the enemy Oscar knows the cryptographic system in use, a hypothesis commonly known as the Kerckhoff principle. Of course Oscar will do this cryptanalysis more difficult if he does not know the cryptographic system in use. However, we do not intend to make the security of the cryptosystem constructed on such a (possibly uncertain) assumption that Oscar does not know the cryptosystem in use. So our goal is to design a secure cryptography under the Kerckhoft principle