CPS: TTP Option: Medium: Collaborative Research: Cyber-Physical System Integrity and Security with Impedance Signatures

网络物理系统（CPS），如汽车、飞机和重型设备，依赖于复杂的分布式供应链，这些供应链从世界各地的制造商那里采购零部件。这些系统面临的一个基本问题是确保通过供应链接收的网络组件和物理部件的安全性、安全性和完整性。由于零件的制造商和消费者之间的分离，在确保实体零件从所需的来源到达并且在运输中不被修改或交换为劣质副本方面存在巨大的挑战。例如，航空航天工业协会表示，“虽然我们知道假冒零件进入了航空航天供应链，但它们进入的时间和地点是不可预测的。”如果这些系统中的网络组件或物理部分被篡改，则会引入重大的网络物理安全风险。例如，拥有零件网络信息的攻击者可以简单地生产假冒零件，克隆任何物理标识符（序列号等），并声称该网络信息是针对被克隆零件的。虽然存在诸如信任根和签名链之类的网络安全技术来帮助确保软件的完整性，但没有相应的信任根和签名链来保证网络组件和物理部件的来源和完整性。因此，存在一种风险，即供应链中使用的算法和控制方法无法识别假冒零件的劣等性能特征，并以不安全的方式控制其操作。本研究的主要目标是创建一个基于物理不可克隆功能的完整性机制，以确保整个CPS是由可信的软件和物理部分构建的。为了实现这一目标，该研究调查了(i)物理测量技术（机电阻抗），为部件提供不可克隆的物理身份；（ii）网络签名方法，从这些身份建立信任链。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Cyber-physical systems (CPS), such as automobiles, planes, and heavy equipment rely on complex distributed supply chains that source parts from manufacturers across the world. A fundamental problem that these systems face is ensuring the safety, security, and integrity of both the cyber components and physical parts that they receive through their supply chain. Because of the separation between the manufacturer and the consumer of the part, there are immense challenges in ensuring that physical parts arrive from the desired source and are not modified or swapped for inferior copies in transit. For example, the Aerospace Industries Association states that "though we know counterfeit parts enter the aerospace supply chain, the time and place of their entry is unpredictable." If either the cyber-components or the physical parts being incorporated into these systems have been tampered with, significant cyber-physical security risk is introduced. As an example, an attacker who has a part's cyber-information can simply produce a counterfeit part, clone any physical identifiers (serial numbers, etc.), and claim that the cyber-information is for the cloned part. While cyber-security techniques, such as roots of trust and signing chains, exist to help ensure software integrity, there are no commensurate roots of trust and signing chains that can guarantee the source and integrity of both the cyber components and physical parts. As such, there is a risk that the algorithms and control approaches used in a supply chain will not identify the inferior performance characteristics of a counterfeit part and control its operation in an unsafe manner. The primary goal of this research is to create an integrity mechanism based on physically unclonable functions to ensure that an entire CPS is built from both trusted software and physical parts. To achieve this goal, the research investigates (i) a physical measurement technique (electro-mechanical impedance) to provide parts an unclonable physical identity and (ii) the cyber signing approaches to build chains of trust from these identities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.