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所在平台: Coursera |
课程主页: https://www.coursera.org/learn/symmetric-crypto
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课程名称：对称加密 概述：欢迎参加对称加密课程！对称加密依赖于共享的密钥，以确保消息的保密性，从而防止未授权的攻击者获取信息。课程内容涵盖了代换和置换技术，这是经典密码学的基础，适用于自然语言（如英语）的信息编码。接下来，我们将建立在产品密码的基础上（结合代换和置换/重排），介绍现代块密码，并回顾广泛使用的密码算法，如DES、3-DES和AES。最后，我们通过介绍不同的块密码操作模式（包括ECB、CBC、CFB、OFB和CTR模式），使块密码能够支持可变数据长度。 该课程跨学科开设，是应用密码学专业和应用密码学入门专业的组成部分。 课程大纲： 1. 经典密码：代换 - 描述代换密码技术，并举例说明多个基于代换的经典算法：凯撒密码、单字母密码和维吉尼亚密码（多字母密码的一种）。同时讨论模运算的数学概念，用于描述密码算法。 2. 经典密码：置换 - 学习置换密码，作为对称密码的基本技术之一。定义置换密码和产品密码，并讨论Rail Fence和置换密码的置换示例。 3. 块密码与DES - 介绍基于产品密码的现代密码。首先定义块密码，并与流密码进行对比。然后描述理想块密码的特征，最大化变换次数，以及Feistel密码，这是一种接近理想块密码的实际结构框架。通过研究基于Feistel结构的广泛使用的密码示例，深入学习数据加密标准（DES）。 4. 3-DES和AES - 为了提供比DES更强的安全性，现代对称密码可以使用多种密码或完全不同的算法。本模块回顾了如Triple-DES和AES的示例。 5. 块密码操作模式 - 在给定密码和密钥的情况下，回顾如何在数据跨块时使用块密码操作模式。本模块描述了五种流行的操作模式：ECB、CBC、CFB、OFB和CTR模式。
Name:Classical Cipher: Substitution
Description:This module defines substitution cipher technique and describes multiple examples for substitution-based classical algorithms: Caesar Cipher, Monoalphabetic Cipher, and Vigenere Cipher (which is a type of Polyalphabetic Cipher). We will also discuss the mathematical concepts in Modulo Operations to use them to describe the cipher algorithms.
Name:Classical Cipher: Transposition
Description:This module studies transposition cipher which, along with substitution cipher, provides a base technique for symmetric ciphers. We define transposition cipher and product cipher and discuss transposition examples in Rail Fence and Permutation Cipher.
Name:Block Cipher and DES
Description:This module is about modern ciphers based on product ciphers. We will first define block cipher and contrast it with stream cipher. We will then describe the ideal block cipher, which maximizes the number of transformations, and Feistel Cipher, which is a practical structure framework approximating the ideal block cipher. As a widely used cipher example based on the Feistel Cipher structure; we will study Data Encryption Standard (DES).
Name:3-DES and AES
Description:To provide stronger security than DES, modern symmetric ciphers can either use multiple ciphers or use an entirely different algorithm. This module reviews examples of each in Triple-DES and AES.
Name:Block Cipher Operation Modes
Description:Given a cipher and a key, this module reviews how to use block cipher operation modes when the data spans across multiple blocks. The module describes five popular operation modes: ECB, CBC, CFB, OFB, and CTR mode.
Welcome to Symmetric Cryptography! Symmetric cryptography relies on shared secret key to ensure message confidentiality, so that the unauthorized attackers cannot retrieve the message. The course describes substitution and transposition techniques, which were the bases for classical cryptography when the message is encoded in natural language such as English. Then, we build on product ciphers (using both substitution and transposition/permutation) to describe modern block ciphers and review the widely used cipher algorithms in DES, 3-DES, and AES. Lastly, we enable the use of block ciphers to support variable data length by introducing different modes of block cipher operations in ECB, CBC, CFB, OFB, and CTR modes. This course is cross-listed and is a part of the two specializations, the Applied Cryptography specialization and the Introduction to Applied Cryptography specialization.
