A RISC-V Instruction Set Extension for Flexible Hardware/Software Protection of Cryptosystems Masked at High Orders

The paper presents an instruction set extension for the CV32E40P RISC-V processor core to protect cryptosystems against side channel attacks using masking at high orders. A first masking order is fixed in hardware at synthesis time. Then a higher masking order is obtained using software composition over the hardware one. The solution has been implemented, validated and evaluated in FPGA.