Improved current flattening circuit using current injection, voltage regulation, and frequency switching

This paper presents a current-flattening circuit which combines current injection, voltage regulation, and frequency switching methods. The circuit can protect a cryptographic device, such as a smart card, against differential power analysis attack. The proposed circuit can be integrated with any type of cryptographic processor and does not need any interface with the processor. Simulation results show that the variations in the power supply current profile is attenuated by 92%, while the power consumption overhead is less than 12% of the original power consumption of the cryptographic processor.