基于DES算法的加密和解密实现(VisualStudio2008)(9800字)
今天计算机技术已经带我们进入了一个全新的时代，计算机网络已经显示出广域分布、体系结构开放、资源共享和信道共用等特征，已被广泛用于金融、贸易、商业、企业、教育等各个领域，但是在网络上存储、共享和传输的信息被非法窃听、截取、篡改或破坏而导致的损失也日益严重,鉴于此,数据加密技术显得尤为重要,数据加密技术已随着计算机技术的迅猛发展，由早期的军事和外交领域，逐步伸展到交通、工业经济、科学技术、社会安全和公共生活的各个领域，成为现代社会中保护信息的重要手段和工具。
本文详细地分析了密码学的发展以及分类,分析了DES算法的发展历程以及实现原理，实现了基于DES算法的加密和解密程序设计，指出了DES算法中存在的缺陷，针对DES算法存在的安全隐患，给予了简单说明并提出了改进措施。最后深入探讨了如何提高DES算法的安全性，介绍加强DES算法安全性的几种改进措施，本文根据目前的几种改进方法所受的限制大胆提出了一种新的方案，达到对DES算法进行改良。
关键词：DES;加密；解密；程序实现；改进构想
DES-BASED ENCRYPTION AND DECRYPTION ALGORITHMS TO ACHIEVE
ABSTRACT
Today, computer technology has brought us into a new era, computer network has been shown widely distributed, open architecture, resources Share and share characteristics such as channel, has been widely used in finance, trade, business, business, education and other fields, but the network storage of
Sharing and transmission of information is illegal eavesdropping, interception, tampering or destruction of the growing losses caused by serious view of this, it is particularly important data encryption technology To, data encryption technology has been rapid development of computer technology by the early military and diplomatic fields, and gradually extended to the transport, industrial economy, Science and technology, social security and all areas of public life, a modern society, an important means of protecting information and tools.
This paper analyzes the development of cryptography and classification, analysis of the DES algorithm implementation principle of the development process and realize the DES algorithm based on
Encryption and decryption program design, pointed out the defects in the DES algorithm, for the DES algorithm has potential safety problems, and propose to give a simple description of The improvement measures. Finally, discusses in depth how to improve the security of DES algorithm, DES algorithm to enhance security introduced several improvements, this root According to several methods for improving the current restrictions proposed a bold new program, to make improvements on the DES algorithm.
KEY WORDS： DES, Encryption, Decryption; Program for; Improved vision
目 录
前 言 1
第1章 密码学概述 2
§1.1 对称密码模型 2
§1.2 密码编码学 2
§1.3 公钥密码学 3
§1.3.1 公钥密码学概述 3
§1.3.2 公钥密码学的应用 4
第2章 DES加密算法 4
§2.1 DES算法发展与概述 4
§2.2 DES算法原理 6
§2.2.1 初始置换 6
§2.2.2 逆置换 6
§2.2.3 密钥处理 6
§2.2.4 DES的迭代 7
第3章 程序实现 8
§3.1 设计构想 8
§3.2 关键算法 8
§3.3 程序测试 13
§3.3.1 测试目的 13
§3.3.2 测试过程 13
§3.3.3 测试结果 14
第4章 DES的安全性问题以及改进构想 15
§4.1 DES存在的安全问题 15
§4.2 DES改进构想 15
§4.2.1 改进构想提出背景 15
§4.2.2 改进构想分析 16
结 论 18
参考文献 19
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