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北京邮电大学毕业设计

实现文件简单的加密和解密

摘要

随着信息社会的到来，人们在享受信息资源所带来的巨大的利益的同时，也面临着信息安全的严峻考验。信息安全已经成为世界性的现实问题，信息安全问题已威胁到国家的政治、经济、军事、文化、意识形态等领域。同时，信息安全也是人们保护个人隐私的关键，是社会稳定安全的必要前提条件。

信息安全是一个综合性的交叉学科领域，广泛涉及数学、密码学、计算机、通信、控制、人工智能、安全工程、人文科学等诸多学科，是近几年迅速发展的一个热点学科领域。信息对抗和网络安全是信息安全的核心热点，它的研究和发展又将刺激、推动和促进相关学科的研究与发展。现今，加密是一种保护信息安全性最有效的方法。密码技术是信息安全的核心技术。

本文是一篇关于文件简单加密和解密软件——文件管家的毕业设计论文：用AES算法实现文件的加密和解密，用MD5实现文件校验功能，用覆盖技术实现文件粉碎功能；并且设计了一套完整的注册码验证体系，防止软件被逆向，从而保护软件的安全。

关键词：文件；加密；解密；粉碎；反逆向；AES

i

北京邮电大学毕业设计

Simple implementation file encryption and decryption

Abstract

With the arrival of the information society, people not only enjoy the enormous benefits of information resources, but also face the severe challenges of information security. Information security has become a worldwide problem. The problem has become a threat to the political, economic, military, cultural, ideological and other aspects of a country. Meanwhile, the information security is the key of protecting individual privacy and the prerequisite for social stability and security.

Information security is a comprehensive interdisciplinary field, involving a wide range of disciplines such as mathematics, cryptography, computer, communications, control, artificial intelligence, security, engineering, humanities and so on, It has been being a hot subject with rapid development. Information countermeasure and network security is a core focus, whose research and developments will stimulate and accelerate the study and progress of related disciplines. So far, the password to information security technology is the most effective method. Cryptography is the core technology of information security.

This article is about a software named File Manager, which can simply encrypt and decrypt files. The software uses AES algorithm to encrypt and decrypt files, MD5 to check the files, and overlay technique to achieve the feature of file shredder. Meanwhile, there is a complete set of design registration code verification system, which is used to protect the software from reverse, thus to protect the security of the software.

Key words：file; encrypt; decrypt; shredder; Anti-Reverse; AES

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北京邮电大学毕业设计

目 录

摘要 ................................................................................................................................................................ i Abstract .......................................................................................................................................................... ii 1 绪论.......................................................................................................................................................... 1

1.1 论文背景 ......................................................................................................................................... 1 1.2 主要工作 ......................................................................................................................................... 1 1.3 本文结构 ......................................................................................................................................... 1 2 AES介绍 ................................................................................................................................................. 2

2.1 AES概述 ......................................................................................................................................... 2 2.2 轮密钥加 (AddRoundKey) ............................................................................................................ 3 2.3 字节替代 (SubBytes) ..................................................................................................................... 3 2.4 行移位 (ShiftRows) ....................................................................................................................... 5 2.5 列混淆 (MixColumns) ................................................................................................................... 6 2.6 密钥调度 (Key Schedule) .............................................................................................................. 7 3 系统设计 .................................................................................................................................................. 8

3.1 设计概述 ......................................................................................................................................... 8

3.1.1 界面设计 .............................................................................................................................. 8 3.1.2 实现代码设计 ...................................................................................................................... 8 3.1.3 操作流程 .............................................................................................................................. 8 3.2 界面设计 ......................................................................................................................................... 9

3.2.1 LOGO设计 ........................................................................................................................... 9 3.2.2 加密选项卡的设计 ............................................................................................................ 10 3.2.3 解密选项卡的设计 ............................................................................................................ 11 3.2.4 工具箱选项卡的设计 ........................................................................................................ 12 3.3 实现代码设计 ............................................................................................................................... 12

3.3.1 加密选项卡的设计 ............................................................................................................ 13 3.3.2 解密选项卡的设计 ............................................................................................................ 14 3.3.3 工具箱选项卡的设计 ........................................................................................................ 15 3.3.4 程序流程图 ........................................................................................................................ 16

4 设计结果及分析 .................................................................................................................................... 20

4.1 设计结果展示 ............................................................................................................................... 20

4.1.1 软件初始化 ........................................................................................................................ 20 4.1.2 注册码验证 ........................................................................................................................ 22 4.1.3 文件加密 ............................................................................................................................ 24 4.1.4 文件解密 ............................................................................................................................ 27 4.1.5 文件校验 ............................................................................................................................ 29 4.1.6 文件粉碎 ............................................................................................................................ 29 4.2 设计结果分析及说明 ................................................................................................................... 30

4.2.1 软件初始化 ........................................................................................................................ 30 4.2.2 注册码验证 ........................................................................................................................ 32 4.2.3 文件加密 ............................................................................................................................ 35 4.2.4 文件解密 ............................................................................................................................ 37