TY - JOUR AU - Banik, Subhadeep AU - Isobe, Takanori AU - Liu, Fukang AU - Minematsu, Kazuhiko AU - Sakamoto, Kosei PY - 2021/03/19 Y2 - 2024/03/29 TI - Orthros: A Low-Latency PRF JF - IACR Transactions on Symmetric Cryptology JA - ToSC VL - 2021 IS - 1 SE - Articles DO - 10.46586/tosc.v2021.i1.37-77 UR - https://tosc.iacr.org/index.php/ToSC/article/view/8833 SP - 37-77 AB - <p>We present Orthros, a 128-bit block pseudorandom function. It is designed with primary focus on latency of fully unrolled circuits. For this purpose, we adopt a parallel structure comprising two keyed permutations. The round function of each permutation is similar to Midori, a low-energy block cipher, however we thoroughly revise it to reduce latency, and introduce different rounds to significantly improve cryptographic strength in a small number of rounds. We provide a comprehensive, dedicated security analysis. For hardware implementation, Orthros achieves the lowest latency among the state-of-the-art low-latency primitives. For example, using the STM 90nm library, Orthros achieves a minimum latency of around 2.4 ns, while other constructions like PRINCE, Midori-128 and QARMA<sub>9</sub>-128- σ<sub>0</sub> achieve 2.56 ns, 4.10 ns, 4.38 ns respectively.</p> ER -