Light-Weight Cipher Based on Hybrid CMOS/STT-MRAM: Power/Area Analysis

Internet of Things (IoT) applications deployment relies on low-power circuits. Nowadays, on top of power consumption, security concern has become a real issue. Light-Weight Cryptography (LWC) has been developed to answer this challenge. In the lightweight cryptographic landscape, the PRESENT algorithm exhibits low power and small area features. At the same time, emergent resistive memory technologies such as Spin Transfer Torque Magnetic Random Access Memory (STT-MRAM) seem to be a strong candidate for Flash replacement with advanced design features such as hybridization with CMOS. In this context, we propose a hybrid CMOS/STT-MRAM technology for PRESENT cryptographic circuit for normally-off IoT applications. We demonstrate that the hybrid implementation is more power-efficient than the CMOS implementation when switched off for a period longer than 49.1 ms for a 180 nm CMOS core process with an area overhead of ×7. Based on this result, trends down to 28 nm node are studied and lead to outstanding performances with a power-effeciency of the hybrid version reached after 185 µs standby mode. In this scenario, an energy of 6,1 pJ is sufficient to store data in the Non-Volatile Flip-Flops (NVFFs) with a reduced area overhead of ×0.23.