A New Scheme to Extract PUF Information by Scan Chain
Aijiao Cui, Wei Zhou, Gang Qu, Huawei Li · 2018
Physical unclonable function (PUF) has been widely investigated as a potential security primitive. The unexpected and unclonable PUF information usually serves as a unique ID or secret key in various application scenarios. How to retrieve the PUF information securely at a reasonably low cost is then a concern. In this paper, we propose a new scheme to extract the PUF information by scan chain. PUF information is used to monitor the test control port (tc) of some specific scan cells at certain time. The output response under a designer-specific test vector is hence obfuscated. The difference between the obfuscated output and the normal output can be used to deduce the PUF information. By reusing the existing scan chain design, the design for PUF extraction cannot be removed easily and it incurs negligibly low overhead. As the specific test vector and related design detail are both unknown to others except designer, the probability for an attacker to figure out the PUF information is sufficiently low. This scheme to extract PUF information can be applied in metering technique or other security-sensitive scenarios.