Feature Reconstruction: Far Field EM Side-Channel Attacks in Complex Environment

Far Field EM Side-Channel Attacks (FEM-SCAs) have emerged as a realistic security threat to widely deployed RF-integrated IoT edge devices. In mixed-signal chips, side-channel leakage may unintentionally couple with transmission signals and be emitted via the on-chip antenna, potentially allowing adversaries to extract sensitive information from the victim at long distances. However, in practical scenarios, far field EM traces captured at long distances usually suffer from noise and interference, which makes the attack less efficient or sometimes even unfeasible. In this paper, we propose a Domain-Adversarial ReFeature Nueral Network (DAR-NN) to facilitate “noisy-clean” adaptation for far field EM traces captured at long distances. By integrating a DAE model with two deep-learning classifiers as regularization terms, the proposed DAR-NN model can reconstruct features of traces obtained remotely in complex environments, thereby achieving a more efficient FEM-SCA. We first test our model by using a publicly available dataset and show that it is feasible to extract the AES key from 141 traces captured at 15 m distance to the victim, which is 58.7% more efficient than existing methods with 80% less profiling data. Afterwards, we set up a more complex experimental environment with a HackRF radio serving as an interference source. We show that the proposed model can still extract the key by using around 2K traces at 15 m even in the presence of 25% active interference, while the state-of-the-art model fails under same conditions.