Digital Signatures and Message Authentication Code (MAC) overview Suppose Alice and Bob share a secret key k which determines hash function hk Alice sends (x, y) to Bob where y = hk

Definition: Group A set G of elements and operator @ form a group if: for all x,y in G, x @ y is also in G (inclusion) there is an identity element e such that for all x in G, e@x = x for all x in G, there is an inverse element x

A. J. Menezes, P. C. van Oorschot and S. A. Vanstone. Handbook of Applied Cryptography, CRC Press, 1997. Bruce Schneier. Applied Cryptography, Second Edition: Protocols, Algorthms, and Source Code in C (cloth) John Wiley & Sons, Inc.) 1996 Douglas R. Stinson, Cryptography (Theory and Practice), CRC Press 1995 Resources

Diffie-Hellman Diffie-Hellman is a public key distribution scheme First public-key type scheme, proposed in 1976. W Diffie, M E Hellman, \New directions in Cryptography\, IEEE Trans. Information

• 信息系统安全概述 • 风险评估 • 古典密码概述 • 对称密码算法 • 非对称密码算法 • 密码应用和网络安全 • 计算机病毒概述， • 典型计算机病毒分析， • 网络攻击与防范

复旦大学：《信息安全原理》课程教学资源（PPT课件）第2章 密码学概论（3/3）、第3章 现代加密算法（1/4）

复旦大学：《密码学基础》课程教学资源（课件讲稿）01 Classical Encryption Techniques

复旦大学：《密码学基础》课程教学资源（课件讲稿）03 Modern Block Ciphers

复旦大学：《密码学基础》课程教学资源（课件讲稿）05 Message authentication and Hash function

• Public-key Technology Review • Why do we need PKI • Digital Certificate Format • Composition of PKI • PKI Trust Relationship • Application of PKI