Scan-Based Attack on Stream Ciphers：A Case Study on eSTREAM Finalists

While Scan-based DFT improves test efficiency, it also leaves a side channel to the privacy information stored in the chip. This paper investigates the side channel and proposes a simple yet powerful scan-based attack that can reveal the key and/or state stored in the chips that implement the state-of-the-art stream ciphers with less than 85 scan-out vectors.