Periodic Nonuniform Sampling for Enhanced Recognition of Spread Spectrum Clocking-Based Electromagnetic Signature

In today's rapidly evolving technological landscape, information visualization devices (IVDs) play a crucial role amidst an overwhelming flood of information. However, ensuring the electromagnetic (EM) reliability of these devices, especially regarding EM information leakage, is increasingly challenging due to the continuous development of infiltration techniques. While the recently developed DisplayPort protocol provides a relatively robust environment for externally used cables with its complex encoding and scrambling method, internally used protocols like FPD-link remain outdated, relying solely on spread spectrum clocking (SSC) technology. Given the ongoing technological advancements described, conventional countermeasures, such as SSC, once groundbreaking, are now vulnerable to infiltration. If exploited for malicious purposes without public disclosure, this could have severe consequences for anyone living in today's information society. Therefore, aiming to contribute to the existing knowledge base, this article seeks to address an issue arising when applying conventional signal reconstruction techniques, originally designed for EM leakage from devices employing constant clocking, to those utilizing SSC. In addition, it proposes a fundamental concept named periodic nonuniform sampling to mitigate the countermeasure effect given by the SSC. Ultimately, this article aims to raise awareness within the academic community regarding the potential for EM penetration and to facilitate proactive measures to address such occurrences.