# Using your ADC and Backend Capacitors to Authenticate for Free: (Virtually) Free from Database, Enrollment, and Excessive Area/Power Overhead

## TL;DR

This paper introduces a novel, intrinsic, database-free chip authentication method using back-end capacitors integrated with ADCs, offering a more reliable and cost-effective alternative to traditional PUF-based techniques.

## Contribution

It demonstrates how ADCs can be modified for capacitor-based authentication, eliminating the need for dedicated hardware and large signature databases.

## Key findings

- Achieves intrinsic, database-free authentication using back-end capacitors.
- Offers improved reliability over transistor PUFs due to insensitivity to temperature and aging.
- Incurred 3.2% power and 75% active-area overhead, deemed acceptable given the benefits.

## Abstract

Detection of counterfeit chips has emerged as a crucial concern. Physically-unclonable-function (PUF)-based techniques are widely used for authentication, however, require dedicated hardware and large signature database. In this work, we show intrinsic & 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 result in a more reliable authentication than transistor PUF-based authentication. The modifications to conventional ADC incur 3.2% power overhead and 75% active-area overhead; however, arguably, the advantages of the discussed intrinsic & database-free authentication outweigh the overheads. Full version of this article is published at IEEE TVLSI.