An Intrinsic and Database-Free Authentication by Exploiting Process Variation in Back-End Capacitors

Detection of counterfeit chips has emerged as a crucial concern. Physically unclonable function (PUF)-based techniques are widely used for authentication; however, these require dedicated hardware and large signature database. In this paper, we show intrinsic and database-free authentication using back-end capacitors. The discussed technique simplifies authentication setup and reduces the test cost. We show that an analog-to-digital converter (ADC) can be modified for back-end capacitor-based authentication in addition to its regular functionality; hence, a dedicated authentication module is not necessary. Moreover, since back-end capacitors are quite insensitive to temperature and aging-induced variations than transistors, the discussed technique results in a more reliable authentication than transistor PUF-based authentication. Discussed authentication scheme manifests significant resilience against power supply instability. The modifications to conventional ADC incur 3.2% power overhead and 75% active-area overhead; however, arguably, the advantages of the discussed intrinsic and database-free authentication outweigh the overheads.