Simple photonic emission analysis of AES

This work presents a novel low-cost optoelectronic setup for time-and spatially resolved analysis of photonic emissions and a corresponding methodology, Simple Photonic Emission Analysis (SPEA). Observing the backside of ICs, the system captures extremly weak photo-emissions from switching transistors and relates them to code running in the chip. SPEA utilizes both spatial and temporal information about these emissions to perform side channel analysis of ICs. We successfully performed SPEA of a proof-of-concept AES implementation and were able to recover the full AES secret key by monitoring accesses to the S-Box. This attack directly exploits the side channel leakage of a single transistor and requires no additional data processing. The system costs and the necessary time for an attack are comparable to power analysis techniques. The presented approach significantly reduces the amount of effort required to perform attacks based on photonic emission analysis and allows AES key recovery in a relevant amount of time. We present practical results for the AVR ATMega328P and the AVR XMega128A1.