Risk-Aware Leakage Resiliency for Wireless Sensor Network Nodes

Leakage resiliency is a kind of light-weight ways of thwarting side-channel attack (SCA) threat. But the frequent updating of key still brings considerable energy overhead for wireless sensor network (WSN) devices. It is a way of saving energy consumption to update the secret key only when the risk of revealing key accumulates to a dangerous threshold, instead of updating at every run. This paper proposes a risk-aware key updating method for leakage resilient cryptography used by WSN node. It employs an on-the-fly risk monitor to evaluate the real time success rate of potential attacks. A low cost implementation of the monitor hardware is presented in addition. A risk-aware key updating leakage resilient Advanced Encryption Standard (AES) engine was implemented and achieves typically 91.7% decrease in terms of energy with only around 8.5% chance of being cracked and 11.6% additional area.