中国矿业大学：密码学_CRYPTO12（Number Theory）

中国矿业大学：密码学_Hash Functions

中国矿业大学：密码学_NTHEORY2（Group Theory and Number Theory for Cryptology）

中国矿业大学：《密码学》PPT教学课件（曹天杰）

中国矿业大学：密码学_Public Key Cryptography

一、对称加密算法 二、经典密码算法 三、现代密码算法 四、AES 五、随机数发生器

密码学主要包含两部内容，即编码学和密码分析学。 编码学是通过编码技术改变被保护信息的形式，使得 编码后的信息除了指定接收者外其他人无法理解的一门学 问，即加密算法的设计和研究。 密码分析，是研究如何攻破一个密码系统，恢复被隐 藏的信息之本来面目，也就是密码破译技术

Cryptographic protocol – Distributed algorithm – Based on cryptographic building blocks – To achieve a security related goal Examples: – Entity Authentication – Key Establishment:Key Distribution(Key enveloping, Key transport), Key agreement – Electronic Payment

Originally designed to be efficient in hardware . A LOT of money has been invested in hardware. although DES standard is public there was considerable controversy over design – in choice of 56-bit key (vs Lucifer 128-bit) – and because design criteria were classified

Modular arithmetic – Used to define a finite field – a = b mod n means that if a and b are divided by n they produce the same remainder – a*b mod n can result in 0 even if a and b are not 0