A 1.96mm2 low-latency multi-mode crypto-coprocessor for PKC-based IoT security protocols

In this paper, we present the implementation of a multi-mode crypto-coprocessor, which can support three different public-key cryptography (PKC) engines (NTRU, TTS, Pairing) used in post-quantum and identity-based cryptosystems. The PKC-based security protocols are more energy-efficient because they usually require less communication overhead than symmetric-key-based counterparts. In this work, we propose the first-of-its-kind tri-mode PKC coprocessor for secured data transmission in Internet-of-Things (IoT) systems. For the purpose of low energy consumption, the crypto-coprocessor incorporates three design features, including 1) specialized instruction set for the multi-mode cryptosystems, 2) a highly parallel arithmetic unit for cryptographic kernel operations, and 3) a smart scheduling unit with intelligent control mechanism. By utilizing the parallel arithmetic unit, the proposed crypto-coprocessor can achieve about 50% speed up. Meanwhile, the smart scheduling unit can save up to 18% of the total latency. The crypto-coprocessor was implemented with AHB interface in TSMC 90nm CMOS technology, and the die size is only 1.96 mm². Furthermore, our chip is integrated with an ARM-based system-on-chip (SoC) platform for functional verification.