Evolution of Obfuscation-Based Scan Design Techniques

Scan chains inserted into the circuit can be exploited as side channels for attackers. This has led to a growing need for secure scan design. The research in the secure scan design started from primitive techniques that involve adding specific gates in the circuit to hinder the interpretation of output data. Subsequently, various attack methods emerged, leading to the differentiation of secure scan design into various categories. In this survey paper, the technical goal of each approach is introduced first. Subsequently, research evolution of secure scan designs is analyzed, aiming to present the directions for future studies.