The emerging security threats in the integrated circuit (IC) supply chain do not only challenge the chip integrity, but also raise serious concerns on hardware intellectual property (IP) piracy. Hardware design obfuscation is a promising countermeasure to resist reverse engineering attacks and IP piracy. The majority of existing hardware obfuscation methods modify the original finite state machine (FSM) by adding additional state transitions and utilizing a key sequence to lock the transition from the nonfunctional states to the functional reset state. Those methods are effective to prevent attackers from entering the normal functional mode but they lack resilience if the FSM is already in the normal mode. This work proposes to protect all the states with a low-cost state-deflection based obfuscation method, which dynamically deflects state transitions from the original transition path to a black hole cluster if a wrong key is applied. Unlike other works that use static transitions between legal states to black hole states at the design time, this method utilizes a state rotation function (Rotatefunc) and selective register flipping function (Mapfunc) to dynamically control the state deflection paths. Hence, the difficulty of reverse engineering and thwarting register overwrite attacks is increased. Simulations performed on ISCAS’89 benchmark circuits show that the proposed method significantly reduces the difference of the net toggle activities between the correct and wrong key scenarios, and achieves up to 56% higher code coverage than the most efficient obfuscation method. Thanks to the dynamic deflection feature, on average, this method generates about 100 more unique state register patterns than other methods with moderate power increase. Moreover, the proposed method achieves the Hamming distance of primary outputs and state registers close to 50%.
28 November 2018 in IEEE Transactions on Very Large Scale Integration (VLSI) Systems
The growing market share of FPGAs motivates the increasing number of attackers to tamper with FPGA systems. The majority of existing research efforts on FPGA security focus on counterfeiting devices, hardware Trojans, reverse engineering hardware designs via decomposing or decrypting bitstream files, and side-channel analysis attacks. Those attacks are typically limited to the FPGA systems implemented in standalone FPGA devices. As more cloud-based FPGA providers, third-party accelerator suppliers, and open-source FPGA design tools are available for prototyping, hardware acceleration, and high-performance computing, new FPGA utilization models are gradually formed. The increasing number of entities involved in the new FPGA use model leads to the emergence of new security threats and attack surfaces. Although the security issues on FPGA systems design and piracy have been widely investigated, there is limited investigation available disclosing the security threats from the FPGA design tools perspective. This work conducts a comprehensive survey on the FPGA tool security and proposes a thorough security threat landscape for the new FPGA utilization model in the era of machine learning and cloud computing.
We exploit the inherent information redundancy in the control path of Networks-on-Chip (NoCs) routers to manage transient errors, preventing packet loss and misrouting. Unlike fault-tolerant routing, our method does not drop packets when faults occur in routers and thus does not increase the burden on neighboring routers. Unlike the NoC interconnect links, the routing operation is nonlinear and standard error control coding methods cannot be used. Instead, our method exploits existing information redundancy in the router, significantly reducing the area overhead and power consumption compared to triple-modular redundancy (TMR). An analytical reliability model of our method is provided, including parameters such as circuit size, different error rates for logic gates and registers, and the location of a faulty element. Compared to TMR, the proposed method improves the arbiter reliability by two orders of magnitude while reducing the total power and area by 43% and 64%, respectively. Simulations performed on a 4×4 NoC show that our method reduces the average latency by up to 90% and 12% over no-protection and TMR methods, respectively.
Sensor networks and IoT systems have been widely deployed in monitoring and controlling system. With its increasing utilization, the functionality and performance of sensor networks and their applications are not the only design aims; security issues in sensor networks attract more and more attentions. Security threats in sensor and its networks could be originated from various sectors: users in cyber space, security-weak protocols, obsolete network infrastructure, low-end physical devices, and global supply chain. In this work, we take one of the emerging applications, advanced manufacturing, as an example to analyze the security challenges in the sensor network. Presentable attacks—hardware Trojan attack, man-in-the-middle attack, jamming attack and replay attack—are examined in the context of sensing nodes deployed in a long-range wide-area network (LoRaWAN) for advanced manufacturing. Moreover, we analyze the challenges of detecting those attacks.