# A Survey on Recent Advanced Research of CPS Security
## 3 Reviews
### Trusted Computing  
With trusted computing, a computer consistently behaves in expected ways, and those behaviors are enforced by computer hardware and software. Trusted computing allows devices to offer improved security over that which is currently available. How to make CPS more secure with trusted computing is a hot topic of current research. [PERSON] et al. [146] proposed a unique method to trust assessment based on Sancus [155], a minimal hardware-only trusted computing base and protected module architecture. The trust assessment modules are deployed directly on IoT nodes, and these modules execute departures from the unprotected OS. Moreover, the modules can inspect the unprotected domain and report measurements of the node's trustworthiness to a trust management system. By assessing the Contiki OS running on a Sancus-enabled TI MSP430 microcontroller, this inspection mechanism is proven to be efficient in implementation with an acceptable runtime overhead. [PERSON] and [PERSON] [72] proposed a concept of trust that uses game theory to decide whether to trust a message from other components or cloud service that may be compromised. They modeled an interaction among the administrator of a cloud service, an attacker, and a device that decides whether to trust signals from the vulnerable cloud. The framework includes a simultaneous signaling game with the FlipIt game, and their equilibrium outcomes also influence each other. In the experimental period, they utilized the Gestalt Nash equilibrium (GNE) to design a trust mechanism for a cloud-assisted insulin pump. Without the help of historical data, the GNE provides a risk threshold to judge the confidence levels of messages from the cloud. [PERSON] et al. [60] proposed a unique trust evaluation mechanism, experience-reputation (E-R), to prevent malicious users from spreading corrupted or falsified data. In the E-R model, they assessed the quality of contributed data from users with two trust indicators, experience and reputation, and selected the most trustworthy MCS users to gather shared data. To evaluate the trust-based scheme, they deployed several recruitment schemes in an MCS testbed consisting of three types of user models, and the results highlight its strength in helping MCS services to detect intelligent malicious users. Moreover, the proposed recruitment mechanisms were implemented in a real-world IoT service, the Wise-IoT project. [PERSON] et al. [73] proposed an incentivized and decentralized IoT software update delivery network, which is based on trustless proof of distribution. In this network, a vendor uses smart contracts to ensure that distributors obtain digital currency as a reward for delivering an update. To ensure untrusted data exchange, the authors utilized a zero-knowledge contingent payment protocol to establish trust between the IoT device and the software update distributor. This method can significantly increase the number of distributors, thus allowing scale out. CIDER [147] is a novel architecture that can recover IoT devices within a short amount of time, even when attackers have taken full control of all devices. With new trusted computing primitives, namely, _gated boot_ and _reset trigger_, the administrator can instruct CIDER to reset the compromised devices compulsorily and to install the patched firmware. The authors implemented a prototype of CIDER on three popular IoT platforms spanning the range from high to low end, and the evaluation shows that CIDER is compatible with current firmware and that the boot-up delay and runtime overhead are negligible. In 2016, [PERSON] et al. [61] proposed a new adaptive trust management protocol to help social IoT applications choose the best trust parameter settings in communication with others. Their work strikes a balance between trust convergence and trust fluctuation. The authors used two real-world social IoT service composition applications to verify their table-lookup method by analyzing the results dynamically and showed the feasibility of the adaptive trust management scheme.