【作者】 李炜；

【导师】 韩芳溪；

【作者基本信息】 山东大学 ， 计算机应用技术， 2010， 硕士

【摘要】 工作流是针对工作中具有固定程序的常规活动而提出的一个概念。通过将工作活动分解成定义良好的任务、角色、规则和过程来进行执行和监控,达到提高生产组织水平和工作效率的目的,为企业更好地实现经营目标提供先进的手段。然而在现代企业信息资源异构、分布、松散耦合的环境下,传统的工作流系统必然向分布式方向发展。移动Agent技术的出现为构建工作流系统提供了更好的选择。移动Agent具有减少网络流量、适合于移动用户、有利于数据集成、具有并行机制等优点,通过利用代码在网络节点间自主搜集和处理信息。基于移动Agent技术实现的工作流系统可以在一定的程度上解决传统工作流系统目前在性能及应用上的不足。但以移动Agent为范型构造的迁移实例所具有的可迁移性带来的新安全隐患也为迁移工作流系统安全提出了更大的挑战。因此,建立相应的安全机制以尽量减少安全隐患,成为迁移工作流走向实用迫切需要解决的问题。在迁移工作流系统中,由迁移实例的迁移所引发的安全问题可分为工作位置安全问题和迁移实例自身的安全问题两类。在传统的工作流系统中,由于工作位置的固化并不存在任务执行体的安全问题。而在迁移工作流系统中,作为任务执行体的迁移实例无论是在网络上的迁移过程中还是在异地工作位置上的执行过程中都存在着代码、数据及状态被窃取或篡改的安全威胁。基于上述研究背景,本文主要讨论了迁移实例的安全问题。根据迁移实例在迁移过程中存在的遭受窃取或篡改破坏的安全威胁实际,提出了适合于迁移工作流管理系统的迁移实例安全的解决方法,通过一种使用安全代理的主动安全机制来实现迁移实例的自主安全能力,达到保护迁移实例的目的。安全代理为迁移实例提供安全服务,具有对当前执行环境进行危险感知的功能。在安全代理的设计方面,通过对现有的代码迷惑技术的研究提出了相应可行的迷惑变换技术,通过对迁移实例运用迷惑变换技术生成的安全代理可以减小安全代理可读性,增加逆向工程难度,从而隐藏安全代理内部的所映射的迁移实例的代码、数据和状态等。在此基础上,基于危险理论为安全代理构造一个危险感知器来实现对其当前执行状态的实时感知。论文对感知器进行了形式化描述,详细介绍了其中各功能模块的构造。最后,为迁移实例构造了一个主动危险感知模型,并给出实现的主要类设计。该安全模型实现了迁移实例的主动安全能力,从而使迁移实例在迁移过程中能主动避开不安全的工作机,在整体上增强了迁移实例抵御外部破坏的能力。本文深入研究迁移实例安全问题,对实现其解决方法的关键技术进行了探讨并作了初步实现,为迁移工作流系统的应用提供了一套可行的安全方案。更多还原

【Abstract】 As a concept originated to manage those fixed activities of businesses, workflow can execute and monitor these activities by dividing them into well-defined tasks, roles, rules and procedures. As a result, workflow can achieve the aim at improving the organization level of business and work efficiency, and provide an advanced method for enterprises to carry out their business goals more effectively. However, in the heterogeneous, distributed, loosely-coupled environment of modern enterprise information resource, the traditional workflow tends to develop into distributed direction. The appearance of mobile agent technology provides a better way to construct workflow system With code migrating among network nodes to collect and deal with information automatically, it has many advantages such as reducing the network flux, suiting the mobile user, adaptable to data integration and possessing parallel feature, etc. So workflow constructed based on mobile agent technology can solve the deficiencies in performance and application to a certain extent. However, the security risks brought by the migrating characteristic of migrating instance, which is constructed based on the mobile agent paradigm, propose greater challenges to the security of migrating workflow. So, it is an urgently solved problem to build corresponding security mechanism to reduce these security risks.In the migrating workflow system, the security problems brought by migrating instance contain the workplace security problems and the migrating instance security problems. In the traditional workflow system, there are no such security problems on task executors because of the fixed workplaces. Oppositely, in the migrating workflow, there are potential risks for migrating instance as a task executor that its data, code and state may be modified and spied out when migrating and executing. On the basis of above research background, this thesis mainly discussed the security problem of migrating instance, and presented a security policy aimed to migrating instance security and suitable for migrating workflow management system which can protect migrating instance by Initiative security mechanism according to its security risks.The security agent which can provide security service for migrating instance has the ability to detect danger on a host that the migrating instance will arrive latter. In the aspect of security agent design, through the study on time limited black box, we proposed corresponding mess-up transformations on migrating instance to create security agent. The usage of these transformations in migrating instance could reduce the readability for hiding its internal code and data. We also build a danger detection part to detect danger on a host based on danger theory. This thesis gave a formalized description of this entity and discussed its structure in detail. Finally, a initiative security model which can protect migrating instance security initiatively was proposed to enhance the ability of migrating instance to resist outer destroy and the main class was given, too.This thesis went deep into the security problem of migrating instance and discussed its essential technical implement, and thus provided a feasible security mode for the application of migrating workflow system.更多还原