【作者】 董林芳；

【导师】 武金木；

【作者基本信息】 河北工业大学 ， 计算机应用技术， 2003， 硕士

【摘要】 在最近的几十年内，计算机与网络发生了巨大的变化，由于这些变化，出现了对大规模电子商务与电子交易系统应用程序安全的更大需求。传统的商务活动所要求的安全、可信、不可伪造和更改，以及发生纠纷时能够仲裁等特点，在以网络和计算机为基础的电子商务活动中同样是必不可少的。而电子文件的易于复制和更改、网络的互连与开放等特点给电子商务增加了方便快捷的同时也增加了更多的不安全因素和新特点。本文正是针对这些不安全因素和新特点提出具有更高可靠性的文件加密和数字签名算法，并以此为基础实现网上电子签约，为日新月异的电子商务提供更广阔的发展空间。 本文首先讨论计算机安全和密码学的一般概念，然后介绍现代加密手段常用的方法和技术，详细讨论了对称加密方法、公开密钥加密方法和单向散列加密方法的优点和不足，进而提出了一种新型的分组加密算法—排列码加密算法，并在此基础上实现了保密散列数字签名算法和有可信第三方参与的网上电子签约。保密散列数字签名算法利用RSA公钥密码体制的原理、MD5单向散列函数和排列码加密的思想，构造了一种能够快速实现数据保密、数字签名的签名方案。更多还原

【Abstract】 Computer and net have taken great changes in recent decades, and these changes made the large-scale electronic commerce and trade systems having more security demands. The characteristics of the traditional business affairs such as security, creditable, unforgeable or unmodify, and can be arbitraged when any dissension occurred are all absolutely necessarily in the electronic commerce based on net and computer. The characteristics that the electronic files are easily copied and modified, the nets are interlinked and open make the electronic commerce not only more quick and easy but also insecurity. This thesis brings forward a new encryption algorithm and a digital signature algorithm that aim at the insecure factors. At the base of these algorithms we can realize the online electronic contracting.In this paper we firstly discuss the general concepts of compter security and cryptology, and then describe the mostly used modern encryption methods and technologies. We detail the advantages and disadvantages of symmetric algorithm, public-key algorithm and one-way hash function. At last we put forward a new block cipher - permutation code, and describe the secret hash digital signature and online electronic contracting with the trusted third party system. The secret hash digital signature is a new siganture method that combines the ideas of RSA public-key algorithm, MD5 one-way hash function and permutation code at the same time.更多还原