密码编码学与网络安全第四版-第二章答案翻译.pdf

第二章

2.1 什么是对称密码的本质成分？

Plaintext, encryption algorithm, secret key, ciphertext, decryption algorithm.

明文 加密算法 密钥 密文 解密算法

2.2 密码算法中两个基本函数式什么？

Permutation and substitution.

代换和置换 P20

2.3 用密码进行通信的两个人需要多少密钥？

对称密码只需要一把，非对称密码要两把 P20

2.5 攻击密码的两种一般方法是什么？

Cryptanalysis and brute force.

密码分析和暴力破解

2.6 列出并简要定力基于攻击者所知道信息的密码分析攻击类型。

Ciphertext only. One possible attack under these circumstances is the brute-force

approach of trying all possible keys. If the key space is very large, this becomes

impractical. Thus, the opponent must rely on an analysis of the ciphertext itself,

generally applying various statistical tests to it.

Known plaintext.The analyst may be able to capture one or more plaintext messages

as well as their encryptions. With this knowledge, the analyst may be able to deduce