Information leakage from the unintentional emissions of an integrated RC oscillator

Recently, it has been shown that electromagnetic radiation from electrical device leaks internal information. A number of studies have been conducted on measurement methods for information leakage, countermeasure technologies, and the propagation mechanism and acquisition of information via electromagnetic fields. Some investigations have shown that information leaks through the clock frequency and higher harmonic waves. Thus, previous studies have focused on the acquisition of information from the change in the amplitude of the clock signal or its harmonic signal. However, there has been little discussion about the acquisition of information by using fluctuations of the clock in the frequency domain. In this paper, we focus on the clock frequency of the integrated RC oscillators that is changed by phase noise and clarify the impact of the frequency shift on the acquisition of information.