摘要移动互联网的迅速发展使得手机应用不断丰富，智能手机的快速兴起为现代人们的 生活带来了全新的体验。然而，人们在尽情享受这些全新体验的同时也面临着日益突出 的手机信息安全问题。所以，手机文件的加密成为大家关注的焦点问题。78330

本文研究了 Android 平台体系结构以及加密技术，设计并实现了一款运行在 Android 平台下的文件加密应用软件。该软件采用了 AES 加密算法和 DES 加密算法，能 够安全有效地为用户提供手机文件信息加密服务。该软件主要包括加密模块、解密模块 和删除模块，主要用于对文件的加密、解密和删除。

在平台选择方面，选择了 Android 平台作为开发平台，它具有完整、开源、免费等 优点，是目前最流行的手机开发平台，已经受到广大开发人员的青睐。在加密技术方面， 介绍了密码学的基本理论和两种常用的加密算法：AES 和 DES。由于在课题中采用这两 种加密算法，只要用户在加密的时候输入秘钥，给文件加密。打开的加密文件就是乱码， 别人不可能知道用户的加密信息。最后，对应用软件的功能实现和系统性能进行了从单 元测试的各个测试。测试结果表明，本次毕业设计实现的加密应用软件能够实现对手机 文件的加密功能，成功地将 AES 算法和 DES 算法应用到了移动手机平台。

毕业论文关键词：Android；DES 加密算法；AES 加密算法；信息安全

Abstract With the rapid development of mobile Internet, the application of mobile phones has been enriched, and the rapid rise of smart phones has brought a new experience for the modern people's life。 However, people enjoy these new experience at the same time also facing increasingly prominent mobile data security issues。

At first, this paper analyzes the problems faced by the current smart phone information security, introduced to guarantee the information security methods, then expounds  the Android system structure and each part, further discusses several commonly used encryption algorithms。 Again on the basis of the eclipse integrated development environment, Java programming language, the design and implementation of the a Android platform based file encryption system。 The whole system is pided into three modules: file browsing module, file encryption module and file decryption module, in the encryption module provides a variety of encryption algorithms to encrypt files, in decryption module to simplify the user operation, improving convenience。

In the platform selection, the choice of the Android platform as a development platform, it has a complete, open source, free of charge, and other advantages, is the most popular mobile phone development platform, has quickly been favored by the majority of developers。 In the aspect of encryption technology, DES and AES encryption technology is selected。

At last, the function realization and system performance of the application software are tested from the unit test, in order to ensure the stability and the compatibility of the application software。 The test results show that this graduation design and implementation of encryption software can realize to mobile phone file encryption, DES and AES algorithm is applied to the mobile phone platform successfully, and the software can consume less resources in stable and safe operation, effective protection of mobile phone file information security and enhance the efficiency of encryption and decryption and user experience。

Key words: Android; DES; AES; Information Safety

目 录

第一章 绪论 1

1。1 研究背景 1

1。2 研究目的及意义