High efficiency power obfuscation switched capacitor dc-dc converter architecture

Abstract

Side channel attacks (SCA) such as correlation power analysis (CPA) have been demonstrated to be very effective in breaking cryptographic engines. The inherent dependence of the power consumption on the secret key can be exploited by statistical analysis to retrieve the key. Various embodiments disclosed herein relate to a new power obfuscation switched capacitor (POSC) DC-DC converter design, which can conceal the leakage of information through power consumption. It works by adding an extra phase to the conventional two-phase switched capacitor (SC) converter, during which a part of the charge from the flying capacitor is extracted and stored on a storage capacitor. This guarantees that the same amount of charge is drawn from the input power supply in each cycle. The design was successfully evaluated by analyzing the power supply to an Advanced Encryption Standard (AES) unit powered by the converter.