网络协议毕业设计.docVIP

摘 要 网络协议是互联网通信的基本构架，不完备或错误的协议往往给攻击者提供了攻击的机会。因为协议本身的高并发性以及所处环境的复杂性，网络协议的设计是非常困难的。我们可以通过对协议设计完毕后进行安全建模，并进行自动化验证，来找到协议设计存在的安全隐患。 在本文中，我们用两种方法分别对BGP协议进行建模。方法一基于规则推理，对协议进行完全分析，得到协议资源和具有某种推导关系的行为，基本资源可以作为协议行为的参数，通过用AND和OR来表示协议行为的推导关系。将此方法应用到BGP协议，最终在BGP协议的攻击规则图上得到了29条攻击路径。方法二用CSP对协议建模，用CSP来表示协议之间各个进程的并发作用，模型包括协议本身、攻击者，以及所要满足的安全约束。并用FDR检验所建立的模型是否满足约束。用该方法来对BGP进行建模验证，检验结果为，该模型满足其中一个约束，而另一个没有被满足的约束得到了一个反例序列。 本文提出了两种对协议进行分析以及建模的方法，一种是基于规则的，一种是用形式化的方法来进行建模。通过这两种方法，我们可以用建立的模型来准确的描述网络协议，使得更好的理解网络协议，并通过对协议的有效分析与验证，得到协议的攻击方法与协议的缺陷。 关键词：CSP；网络协议；规则；安全建模；BGP协议 ABSTRACT Network protocol is the basic framework of Internet communications, however, the incomplete or incorrect protocol often provides attackers some opportunities. Because of the high concurrency of a network protocol and the complexity of the environment where it works, it is difficult to design a network protocol with a reliable safety. We can find out a network potential’s safety hazard through security modeling and automated verification. In this paper, we’ll use two methods to model on the BGP protocol. The first method bases on the rule-based reasoning approach to analyze the protocol and get protocol resources as well as behaviors which have some kinds of derived relations. The basic resources serve as the parameters of the protocol’s behaviors and indicates the derived relations by “AND” and “OR”. Applying this method to BGP protocol, we successfully get 29 attack paths on the attacking rules diagram. The second method is to model with CSP. We’ll use CSP to indicate the concurrency effect of every process among the protocols. This model contains not only the protocols but also the attackers and the security constraints which need to be satisfied. At the same time, we use FDR to test this model to exam whether it meets the constraints. In this way, we testify the BGP and the result is that one of the two constraints is satisfied while the other is unsatisfied from which we get a counter-example sequence. We propos