信息安全导论(密码学)期末复习汇编.ppt

* Final Review 胡海波 page* 2. 对称密码 2.2 流密码 Structure 01101100+ plaintext key stream ciphertext * Final Review 胡海波 page* 2. 对称密码 2.2 流密码：RC4算法 * Final Review 胡海波 page* 2. 对称密码 2.2 流密码：RC4算法 * Final Review 胡海波 page* 2. 对称密码 2.2 流密码：RC4算法 Initialization Initialization is done in two steps: Key Stream Generation The keys in the key stream are generated, one by one. * Final Review 胡海波 page* 2. 对称密码 2.3 秘钥分配 Key Distribution Scenario: preconditions(前提) A wishes to establish a logical connection with B A B KDC A requires a session key from KDC to protect the communication A share a master key with KDC, B share with KDC Secret channel Secret channel * Final Review 胡海波 page* 2. 对称密码 A KDC A B 1 2 4 5 6 2.3 秘钥分配：KDC Scenario * Final Review 胡海波 page* 2. 对称密码体系 3. 公钥密码体系 4. 密码散列函数 密码学原理及算法 1. 概述 * Final Review 胡海波 page* 3. 公钥密码 3.1 Diffie-Hellman Key Exchange Scheme * Final Review 胡海波 page* 3. 公钥密码 3.1 Diffie-Hellman Key Exchange Scheme Global Public Elements Y：Y<P, Y是P的素数根 P：素数 For Alice Selected private: A, ( A<P ) Calculate public α=YA mod P For Bob Selected private B, ( B<P ) Calculate public β=YB mod P For Alice Key= βA mod P For Bob Key= αB mod P * Final Review 胡海波 page* 3. 公钥密码 3.2 RSA Principles of RSA For plaintext M and ciphertext C, assume that we can find integers e, d, and n such that: * Final Review 胡海波 page* 3. 公钥密码 3.2 RSA Key Generation of RSA 1. Choose two (large) prime number p, q privately 2. Calculate 3. Choose e with 4. Calculate 5. Publicize {e,n} and keep d private * Final Review 胡海波 page* 2. 对称密码体系 3. 公钥密码体系 4. 密码散列函数 密码学原理及算法 1. 概述 * Final Review 胡海波 page* 4.密码散列函数 * Final Review 胡海波 page* 4.密码散列函数 消息鉴别 M M Hash MD M MD Hash MD MD’ I N T E R N E T * Final Review 胡海波 page* 组合应用：PGP M SHA-1 RSA M N-bit session key AES RSA C Internet C RSA AES N-bit session key M RSA SHA