Lightweight authenticated ciphers are crucial in many resource-constrained applications, including online payments and the Internet of Things. The US National Institute of Standards and Technology (NIST) coordinates a standardization process, currently in Round 3, to select lightweight algorithms for such applications. Although security is paramount, cost, performance, and resistance to side-channel attacks are among the most critical selection criteria. This paper investigates the effect of applying side-channel countermeasures on the cost and performance of three NIST Lightweight Cryptography Finalists:  Elephant, TinyJAMBU, and Xoodyak. For all investigated algorithms, we apply Domain-Oriented Masking. We then compare the cost of protection in terms of resource utilization and performance.

Our first-order protected designs of Elephant, TinyJAMBU, and Xoodyak occupy 5451, 1267, and 6431 LUTs and have a throughput of 93, 120, and 891 Mbps, respectively, when implemented on Xilinx Artix-7 FPGAs.