Protecting data and hardware is vital, driving the adoption of Physically Unclonable Functions (PUFs) for generating unique circuit signatures. This paper introduces a fault-tolerant system featuring a ring-oscillator (RO) based PUF, utilizing a reversible logic (RL) design. The proposed system comprises various sub-systems such as Fault-Tolerant RL-based inverter design, Reversible-Logic designing, Fault-Detection module, Fault-free path selection module, and the Reversible RO-PUF module. The proposed design is implemented on a Basys-3 FPGA board for calculating various PUF parameters. It is observed that the uniqueness, uniformity, and bit-aliasing of the proposed design at 27°C are 49.40%, 51.20%, and 48.30%, respectively. Further, bit-error-rate (BER), reliability, and key error rate (KER) are determined at three different temperatures, and the best results obtained are 0.003%, 99.7%, and 0.092 at 40°C, respectively. Compared to conventional PUFs, the proposed design showcases higher reliability (0.002% to 0.11%) and significantly reduced BER and KER ($1.67\times $to$22.67\times $, and$1.6\times $to$8.02\times $respectively). The proposed design also passed 15 NIST tests against conventional RO-PUF, which could pass only 11 NIST tests. We have also tested the resilience of different PUF designs against three machine-learning models with the best accuracy of 58.9% against the Logistic Regression model.

Extremely energetic particles prevalent in the nuclear environment make memory cells prone to soft errors. Also, attackers extract secret data of SRAM cells via side-channel attacks (SCAs), and leakage power analysis attacks (LPAs) are a serious threat to security systems. This research indicates an extremely effective radiation-hardened and LPA-resilient (RHLR12T) SRAM cell that is both radiation resistant by design for nuclear applications and LPA-resilient. It offers better speed, enhanced writing stability and higher overlap percentage compared to other considered SRAM cells, such as 6T, Quatro, We-Quatro, and RHMD10T, utilizing 45nm CMOS technology at the supply voltage of 1.0V and 27-C operating temperature. The proposed cell gives 1.141× higher write stability, 1.55× lower write access time, 1.11× increased critical charge and 1.51× better overlap percentage than RHMD10T SRAM cell.

In this paper, a new XOR gate is discussed in quantum-dot cellular automata (QCA). The proposed gate is a single layer structure with no crossovers, and has been designed with redundant cells to increase the amplitude of the output signal and to improve the fault tolerance and reliability of the circuit. Based on the performance comparison, the investigated XOR gate has very high fault tolerance to single-cell addition and single-cell omission defects, thereby making them suitable candidates for designing reliable QCA based digital circuits.

The achievable secrecy rate regions of various multi‐user channels with Gaussian inputs are well‐known in the literature. To gain more practical insights into the achievable rates, it is more useful to consider channels with inputs from finite constellations, such as M‐ary quadrature amplitude modulation (M‐QAM), M‐ary phaseshift keying (MPSK), M‐ary amplitude phase‐shift keying (M‐APSK) etc. The authors study the achievable secrecy rates with a constrained constellation input for a multiple access wiretap channel with an eavesdropper. They also show that if the constellation points are rotated relatively for the two users then the secrecy sum‐rate can be improved. They perform Monte–Carlo simulations for computing these secrecy rates for classical modulation schemes including BPSK, quadrature phase‐shift keying, M‐QAM, M‐PSK, M‐PAM, and M‐APSK. They also derived an approximate function, whose argument of supremum provides an approximately optimal rotation angle for obtaining a maximum secrecy sum‐rate. they also show, via simulations, that rotation of constellation is helpful for some range of signal‐to‐noise ratio only, which is contrary to the results of multiple access channel without security constraint. Finally, they consider a more realistic scenario, where the channel from transmitters to receivers and eavesdroppers is time‐varying. They consider the case of complex circularly symmetric Gaussian random channel gains and compute the optimal rotation angle, which will maximise the expected value of an upper bound of the secrecy sum‐rate.