A New Secure Scan Design with PUF-based Key for Authentication

Scan-based side-channel attack has become a new threat to cryptographic chips. Many countermeasures are proposed to safeguard scan design against the scan-based attacks. Among which, the methods based on lock and key scheme present more effective and popular. In this paper, we propose a new lock and key scheme which adopts physical unclonable function (PUF) design to generate a unique key for each design. The uniqueness of PUF enables each chip taped out from one mask to possess a different golden key. Once the PUF is invoked for the first time, the PUF response will be hardcoded into the design so that even the environment changes, the PUF-based key maintains. The proposed secure scan design with PUF-based key can protect the cryptographic chips against all known scan-based side-channel attacks while incurring negligible overhead.