Rapid Prototyping of CRYSTALS-Kyber Primitives on FPGA using Python-only HW-SW Flow

Post-quantum cryptographic (PQC) algorithms are being standardized to prepare for the quantum computing era. CRYSTALS-Kyber is the chosen PQC scheme for Public Key Encryption. Number Theoretic Transforms (NTT) and SHA-3 core are the key primitives used in CRYSTALS-Kyber. Hence, fast and efficient implementations of these primitives are important. Typically, rapid prototyping of hardware blocks is done using tools like Vivado HLS. However, HLS tools don’t always produce optimal results and the generated RTL code is not portable across platforms. This paper implements NTT and SHA-3 cores using a Python-based DSL to generate synchronous digital circuits, which perform better than Vivado HLS. The tool is lightweight and easy to use and the generated RTL is portable for any FPGA or ASIC flows. Moreover, due to the availability of the PYNQ-Z2 framework, FPGA-based testing can be done using Python, enabling Python-only hardware-software flow.