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Lightweight authenticated ciphers are crucial in many resource-constrained applications, including hardware security. To protect Intellectual Property (IPs) from theft and reverse-engineering, multiple obfuscation methods have been developed. An essential component of such schemes is the need for secrecy and authenticity of the obfuscation keys. Such keys may need to be exchanged through the unprotected channels, and their recovery attempted using side-channel attacks. However, the use of the current AES-GCM standard to protected key exchange requires a substantial area and power overhead. NIST is currently coordinating a standardization process to select lightweight algorithms for resource-constrained applications. Although security against cryptanalysis is paramount, cost, performance, and resistance to side-channel attacks are among the most important selection criteria. Since the cost of protection against side-channel attacks is a function of the algorithm, quantifying this cost is necessary for estimating its cost and performance in real-world applications. In this work, we investigate side-channel resistant lightweight implementations of an authenticated cipher TinyJAMBU, one of ten finalists in the current NIST LWC standardization process. Our results demonstrate that these implementations achieve robust security against side-channel attacks while keeping the area and power consumption significantly lower than it is possible using the current standards. 

Logic locking has been widely evaluated as a proactive countermeasure against the hardware security threats within the IC supply chain. However, the introduction of the SAT attack, and many of its derivatives, has raised big concern about this form of countermeasure. In this paper, we explore the possibility of exploiting chaos computing as a new means of logic locking. We introduce the concept of chaotic logic locking, called ChaoLock, in which, by leveraging asymmetric inputs in digital chaotic Boolean gates, we define the concept of programmability (key-configurability) to the sets of underlying initial conditions and system parameters. These initial conditions and system parameters determine the operation (functionality) of each digital chaotic Boolean gate. Also, by proposing dummy inputs in chaotic Boolean gates, we show that during reverse-engineering, the dummy inputs conceal the main functionality of the chaotic Boolean gates, which make the reverse-engineering almost impossible. By performing a security analysis of ChaoLock, we show that with no restriction on conventional CMOS-based ASIC implementation and with no test/debug compromising, none of the state-of-the-art attacks on logic locking, including the SAT attack, could reformulate chaotic Boolean gates while dummy inputs are involved and their parameters are locked. Our analysis and experimental results show that with a low number of chaotic Boolean gates mixed with CMOS digital gates, ChaoLock can guarantee resiliency against the state-of-the-art attacks on logic locking at low overhead. 

Twenty five Round 2 candidates in the NIST Lightweight Cryptography (LWC) process have been implemented in hardware by groups from all over the world. All implementations compliant with the LWC Hardware API, proposed in 2019, have been submitted for hardware benchmarking to George Mason University's LWC benchmarking team. The received submissions were first verified for correct functionality and compliance with the hardware API's specification. Then, the execution times in clock cycles, as a function of input sizes, have been determined using behavioral simulation. The compatibility of all implementations with FPGA toolsets from three major vendors, Xilinx, Intel, and Lattice Semiconductor was verified. Optimized values of the maximum clock frequency and resource utilization metrics, such as the number of look-up tables (LUTs) and flip-flops (FFs), were obtained by running optimization tools, such as Minerva, ATHENa, and Xeda. The raw post-place and route results were then converted into values of the corresponding throughputs for long, medium-size, and short inputs. The results were presented in the form of easy to interpret graphs and tables, demonstrating the relative performance of all investigated algorithms. An effort was made to make the entire process as transparent as possible and results easily reproducible by other groups. 

With the outsourcing of design flow, ensuring the security and trustworthiness of integrated circuits has become more challenging. Among the security threats, IC counterfeiting and recycled ICs have received a lot of attention due to their inferior quality, and in turn, their negative impact on the reliability and security of the underlying devices. Detecting recycled ICs is challenging due to the effect of process variations and process drift occurring during the chip fabrication. Moreover, relying on a golden chip as a basis for comparison is not always feasible. Accordingly, this paper presents a recycled IC detection scheme based on delay side-channel testing. The proposed method relies on the features extracted during the design flow and the sample delays extracted from the target chip to build a Neural Network model using which the target chip can be truly identified as new or recycled. The proposed method classifies the timing paths of the target chip into two groups based on their vulnerability to aging using the information collected from the design and detects the recycled ICs based on the deviation of the delay of these two sets from each other. 

The resource-constrained nature of the Internet of Things (IoT) edges, poses a challenge in designing a secure and high-performance communication for this family of devices. Although side-channel resistant ciphers (either block or stream) could guarantee the security of the communication, the energy intensive nature of these ciphers makes them undesirable for lightweight IoT solutions. In this paper, we introduce ExTru, an encrypted communication protocol based on stream ciphers that adds a configurable switching & toggling network (CSTN) to not only boost the performance of the communication in these devices, it also consumes far less energy than the conventional side-channel resistant ciphers. Although the overall structure of the proposed scheme is leaky against physical attacks, we introduce a dynamic encryption mechanism that removes this vulnerability. We demonstrate how each communicated message in the proposed scheme reduces the level of trust. Accordingly, since a specific number of messages, N, could break the communication and extract the key, by using the dynamic encryption mechanism, ExTru can re-initiate the level of trust periodically after T messages where T <; N, to protect the communication against side-channel and scan-based attacks (e.g. SAT attack). Furthermore, we demonstrate that by properly configuring the value of T, ExTru not only increases the strength of security from per “device” to per “message”, it also significantly improves energy saving as well as throughput vs. an architecture that only uses a conventional side-channel resistant block/stream cipher. 

LowMC is a parameterizable block cipher developed for use in Multi-Party Computation (MPC) and Fully Homomorphic Encryption (FHE). In these applications, linear operations are much less expensive in terms of resource utilization compared to the non-linear operations due to their low multiplicative complexity. In this work, we implemented two versions of LowMC -- unrolled and lightweight. Both implementations are realized using RTL VHDL. To the best of our knowledge, we report the first lightweight implementation of LowMC and the first implementation protected against side-channel analysis (SCA). For the SCA protection, we used a hybrid 2/3 shares Threshold Implementation (TI) approach, and for the evaluation, the Test Vector Leakage Assessment (TVLA) method, also known as the T-test. Our unprotected implementations show information leakage at 10K traces, and after protection, they could successfully pass the T-test for 1 million traces. The Xilinx Vivado is used for the synthesis, implementation, functional verification, timing analysis, and programming of the FPGA. The target FPGA family is Artix-7, selected due to its widespread use in multiple applications. Based on our results, the numbers of LUTs are 867 and 3,328 for the lightweight and the unrolled architecture with unrolling factor U = 16, respectively. It takes 14.21 μs for the lightweight architecture and 1.29 μs for the unrolled design with U = 16 to generate one 128-bit block of the ciphertext. The fully unrolled architecture beats the best previous implementation by Kales et al. in terms of the number of LUTs by a factor of 4.5. However, this advantage comes at the cost of having 2.9 higher latency. 

The globalization of the IC supply chain has raised many security threats, especially when untrusted parties are involved. This has created a demand for a dependable logic obfuscation solution to combat these threats. Amongst a wide range of threats and countermeasures on logic obfuscation in the 2010s decade, the Boolean satisfiability (SAT) attack, or one of its derivatives, could break almost all state-of-the-art logic obfuscation countermeasures. However, in some cases, particularly when the logic locked circuits contain complex structures, such as big multipliers, large routing networks, or big tree structures, the logic locked circuit is hard-to-be-solved for the SAT attack. Usage of these structures for obfuscation may lead a strong defense, as many SAT solvers fail to handle such complexity. However, in this paper, we propose a neural-network-guided SAT attack (NNgSAT), in which we examine the capability and effectiveness of a message-passing neural network (MPNN) for solving these complex structures (SAT-hard instances). In NNgSAT, after being trained as a classifier to predict SAT/UNSAT on a SAT problem (NN serves as a SAT solver), the neural network is used to guide/help the actual SAT solver for finding the SAT assignment(s). By training NN on conjunctive normal forms (CNFs) corresponded to a dataset of logic locked circuits, as well as fine-tuning the confidence rate of the NN prediction, our experiments show that NNgSAT could solve 93.5% of the logic locked circuits containing complex structures within a reasonable time, while the existing SAT attack cannot proceed the attack flow in them.