基于计算机并口的智能软件加密狗设计

文档编号:DZXX046  文档字数:16511,页数:55

摘要

 近些年来，人们开始越来越重视对软件的保护。软件开发者除了采用法律手段保护自己的利益外，还应着重从技术上采取手段保护自己的知识产权，其方法就是采用软件加密技术。微机软件开发商为了保护自己的研究成果， 往往都希望对软件系统进行加密。早期采用的加密方式（如硬盘加密、加密卡等）都因为有这样那样的缺点而被淘汰，取而代之的加密狗加密技术是近几年来兴起的一种较为理想的加密手段。
 加密狗的设计没有千篇一律的模式可循，往往是仁者见仁，智者见智，也正因为如此，加密狗才有对系统加密存在的价值。本文介绍一种高级加密狗技术，它利用插接在微机并行打印口上的加密装置与专用加密程序互相配合来实现对密码的写入、保存、读取和校对。它将密码分成接收码和返回码两部分，接收码由PC机加密软件提供，返回码由接收码和单片机内部软件算法产生，这种加密方式具有保密性更强，破密难度更大，且可应用于不同软件系统等特点。

关键词：软件狗，PIC单片机，加密，并口，解密

ABSTRACT

 In recent years, people have begun paying more and more attention to the protection of the software. Besides legal means, software developer should stress on technical means to protect their own property rights and interests. Software encryption techniques is the way. To protect their own development and research results, computer software developers often want to do software encryption. Early use of encryption methods (such as hard disk encryption, encryption card, etc.) are eliminated, because of all kinds of defects. Instead, encryption technique of softdog is an arising ideal means of encryption in recent years.
 The design and implementation of software has no stereotyped pattern, people can develop and do at their own wise way. And this presents the value of softdog encrypting system. This thesis introduces one kind of super softdog technique. It utilizes the plug-in encryption facility of PC LPT and private encryption procedures to achieve the passwords input, preservation, reading and proof. It has 2 parts of passwords, input codes and return codes. Input codes is from encryption software of PC, and return codes is from input codes & the internal software of SCM. This encryption method is a more confidential, of much more password broken difficulty and can be applied to many different software systems, and other excellent features.
 Keywords: Softdog , PIC MCU, Encryption, Parallel port, Decryption

目录
摘要 I
ABSTRACT II
第1章 绪论 1
1.1 背景 1
1.2 研究内容 2
第2章 设计方案论证 4
2.1 单片机的选择 4
2.2 微机接口的选择 5
第3章 系统硬件设计 6
3.1 单片机简介 6
3.2 打印机端口简介 8
3.3 单片机与打印机端口电路设计 12
3.4 用Protel DXP工具制作原理图和PCB板 13
第4章 系统软件设计 20
4.1 加密算法分析 20
4.1.1 密码学的基本概念 20
4.1.2 三种加密算法的比较 23
4.2 用MPLAB工具调试编程 26
4.3 使用程序外壳工具 29
第5章 毕业设计总结 31
致谢 32
参考文献 33
附录 单片机程序 34

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