Seesaw: A 4096-bit vector processor for accelerating Kyber based on RISC-V ISA extensions

The ML-KEM standard based on Kyber algorithm is one of the post-quantum cryptography (PQC) standards released by the National Institute of Standards and Technology (NIST) to withstand quantum attacks. To increase throughput and reduce the execution time that is limited by the high computational complexity of the Kyber algorithm, an RISC-V-based processor Seesaw is designed to accelerate the Kyber algorithm. The 32 specialized extension instructions are mainly designed to enhance the parallel computing ability of the processor and accelerate all the processes of the Kyber algorithm by thoroughly analyzing its characteristics. Subsequently, by carefully designing hardware such as poly vector registers and algorithm execution units on the RISC-V processor, the support of microarchitecture for extension instructions was achieved. Seesaw supports 4096-bit vector calculations through its poly vector registers and execution unit to meet high-throughput requirements and is implemented on the field-programmable gate array (FPGA). In addition, we modify the compiler simultaneously to adapt to the instruction extension and execution of Seesaw. Experimental results indicate that the processor achieves a speed-up of 432$\times$ and 18864$\times$ for hash and NTT, respectively, compared with that without extension instructions and a speed-up of 5.6$\times$ for the execution of the Kyber algorithm compared with the advanced hardware design.