Making Register File Resistant to Power Analysis Attacks

Abstract — Power analysis attacks are a type of side-channel attacks that exploits the power consumption of computing devices to retrieve secret information. They are very effective in breaking many cryptographic algorithms, especially those running in low-end processors in embedded systems, sensor nodes, and smart cards. Although many countermeasures to power analysis attacks have been proposed, most of them are software based and designed for a specific algorithm. Many of them are also found vulnerable to more advanced attacks. Looking for a low-cost, algorithm-independent solution that can be implemented in many processors and makes all cryptographic algorithms secure against power analysis attacks, we start with register file, where the operands and results of most instructions are stored. In this paper, we propose RFRF, a register file that stores data with a redundant flipped copy. With the redundant copy and a new precharge phase in write operations, RFRF provides data-independent power consumption on read and write for cryptographic algorithms. Although RFRF has large energy overhead, it is only enabled in the security mode. We validate our method with simulations. The results show that the power consumption of RFRF is independent of the values read out from or written to registers. Thus RFRF can help mitigate power analysis attacks. I