Trust Emanates from Within: A Micro-architectural and Compiler Support Framework for Trust

传统的计算机安全假设了一种偏执的世界模型，导致每笔交易都必须通过加密或类似技术来保护。然而，典型的人类交易并不是偏执的，特别是在受信任的各方之间。类似的信任概念也适用于系统级交易，例如电子商务应用程序。信任消除了对计算昂贵的安全技术的需要。传统上，信任是在系统和/或事务级别上定义的。这项拟议的研究开发了一个更低级别的信任定义--具体地说，就是一个程序对自己的可信度进行的自我评估。这种信任定义捕获了与程序流行为的预期规范的任何偏差。程序中的每个点都可以通过一组控制路径到达，其中一条路径由一组特定的输入实例化。然而，在受攻击的程序中，一个全新的控制路径通向被利用的程序点。这种偏离标准的做法降低了该计划的信任值。对规范控制路径的肯定可以提高程序的可信度。当信任值低于某一事务定义的阈值时，该程序可以引发异常以调用系统级入侵检测实用程序。编译器负责为每个程序点构造一组有效的预期路径。处理器微体系结构负责对照实例化的控制路径解释和验证编译器生成的一组有效控制路径。这项研究将开发用于分析和规范有效控制路径的编译器技术。还将探讨本活动所需的微体系结构支持。这项研究的预期影响将是从事务的程序组件提供稳健的信任值，从而使系统级信任更准确地反映系统状态。这应该允许更容易地将信任范例与传统安全技术相结合。

Traditional computer security assumes a paranoid model of the world resulting in a necessity for each transaction to be secured through encryption or similar techniques. However, a typical human transaction is not paranoid, specifically between trusted parties. A similar notion of trust exists for system level transactions such as an e-commerce application. Trust obviates the need for computationally expensive security techniques.Trust has traditionally been defined at system and/or transaction level. The proposed research develops a much lower level definition of trust --specifically a program's self-assessment of its own trustworthiness. This definition of trust captures any deviations from the expected norm for the program flow behavior. Each point in program can be reached through a set of control paths, one of which is instantiated by a specific set of input. In a compromised program, however, an entirely new control path leads to the exploited program point. Such departures from the norm lower the program's trust value. An affirmation of a norm control path can raise the program's trust. When the trust value falls below a certain transaction defined threshold, the program can raise an exception to invoke a system level intrusion detection utility. The compiler is responsible to construct a set of valid, expected paths for each program point. The processor microarchitecture is responsible for interpreting and verifying the compiler generated set of valid control paths against the instantiated control paths. This research will develop compiler technology for the analysis and specification of valid control paths. The required microarchitecture support for this activity will also be explored. The expected impact of this research will be to provide a robust trust value from the program components of a transaction, which in turn makes the system level trust reflect the system state more accurately. This should allow for an easier integration of trust paradigm with the traditional security techniques.