Biblio

In this work, we propose and demonstrate a multi-layer 3-dimensional (3D) vertical RRAM (VRRAM) PUF with in-cell stabilization scheme to improve both cost efficiency and reliability. An 8-layer VRRAM array was manufactured with excellent uniformity and good endurance of \textbackslashtextgreater107. Apart from the variation in RRAM resistance, enhanced randomness is obtained thanks to the parasitic IR drop and abundant sneak current paths in 3D VRRAM. To deal with the common issue of unstable bits in PUF output, in-cell stabilization is proposed by first employing asymmetric biasing to detect the unstable bits and then exploiting reprogramming to expand the deviation to stabilize the output. The bit error rate is reduced by \textbackslashtextgreater7X (68X) for 3(5) times reprogramming. The proposed PUF features excellent resistance against machine learning attack and passes both National Institute of Standards and Technology (NIST) 800-22 and NIST 800-90B test suites.

The globalization of supply chain makes semiconductor chips susceptible to various security threats. Design obfuscation techniques have been widely investigated to thwart intellectual property (IP) piracy attacks. Key distribution among IP providers, system integration team, and end users remains as a challenging problem. This work proposes an orthogonal obfuscation method, which utilizes an orthogonal matrix to authenticate obfuscation keys, rather than directly examining each activation key. The proposed method hides the keys by using an orthogonal obfuscation algorithm to increasing the key retrieval time, such that the primary keys for IP cores will not be leaked. The simulation results show that the proposed method reduces the key retrieval time by 36.3% over the baseline. The proposed obfuscation methods have been successfully applied to ISCAS'89 benchmark circuits. Experimental results indicate that the orthogonal obfuscation only increases the area by 3.4% and consumes 4.7% more power than the baseline1.