TROJANUS: An ultra-lightweight side-channel leakage generator for FPGAs

In this article we present a new side-channel building block for FPGAs, which, akin to the old Roman god of Janus, has two contradictory faces: as a watermarking tool, it allows to uniquely identify IP cores by adding a single slice to the design; as a Trojan Side-Channel (TSC) it can potentially leak an entire encryption key within only one trace and without the knowledge of either the plaintext or the ciphertext. We practically verify TROJANUS´ feasibility by embedding it as a TSC into a lightweight FPGA implementation of PRESENT. Besides, we investigate the leakage behavior of FPGAs in more detail and present a new pre-processing technique, which can potentially increase the correlation coefficient of DPA attacks.