A Memristor-based Secure Scan Design against the Scan-based Side-Channel Attacks

Scan chain design can improve the testability of a circuit while it can be used as a side-channel to access the sensitive information inside a cryptographic chip for the crack of cipher key. To secure the scan design while maintaining its testability, this paper proposes a memristor-based secure scan design. A lock and key scheme is introduced. Physical unclonable function (PUF) is used to generate a unique test key for each chip. When an input test key matches the PUF-based key, the scan chain can be used normally for testing. Otherwise, the data in some scan cells are obfuscated by the random bits, which are generated by reading the status of a memristor. As the random bits do not relate to the original test data, an adversary cannot access useful information from scan chain to deduce the cipher key. The experimental results show that the proposed secure scan design can resist all existing attacks while incurring low overhead. Also, the testability of the original design is not affected.