Strengths and Limitations of High-Resolution Electromagnetic Field Measurements for Side-Channel Analysis

The electromagnetic field as a side-channel of cryptographic devices has been linked to several advantages in past contributions. We provide a comprehensive study using high-resolution horizontal and vertical magnetic field probes at close distance to an integrated circuit die. We configured an FPGA device with two uncorrelated digital structures showing similar leakage behavior as symmetric cryptography implementations. We found that measurements from the frontside of the die using a horizontal probe lead to the highest signal-to-noise ratios. Further, high sampling rates are required and no trace compression should be applied. Contrary to previous contributions, we successfully demonstrate that the leakage of design parts is locally restricted and matches their placement. This proves the feasibility of localized side-channel analysis after a profiling phase, however, also means that other locations will lead to inferior results, which is an important limitation. Our analysis confirmed an advantage of measuring localized electromagnetic fields instead of current consumption due to the fact that less parasitic capacitances are involved.      «

The electromagnetic field as a side-channel of cryptographic devices has been linked to several advantages in past contributions. We provide a comprehensive study using high-resolution horizontal and vertical magnetic field probes at close distance to an integrated circuit die. We configured an FPGA device with two uncorrelated digital structures showing similar leakage behavior as symmetric cryptography implementations. We found that measurements from the frontside of the die using a horizonta...     »