Sonoma State University
CS Colloquium | February 24, 2011

The *Puf* Makes The Difference

Sid Paral and Mandel Yu, Verayo, San Jose, CA

Stevenson Hall 1300
11:00 AM - 11:50 AM

Almost daily, we hear about outrageous cases of product counterfeiting; we all experience increased demands for identification of persons and computer data. Traditional concepts of trust, based on scarcity and secrets, are eroded by perfect digital copies, both in software and hardware. Physical Unclonable Functions (PUFs) offer a solution: they reference objects to measurable qualities outside the creator’s (or would-be counterfeiters) control, with the help of naturally occurring randomness. In our team, we focus on silicon chips built in a standard manufacturing process, and in particular, on their differential timing performance, rooted in random manufacturing process variations - still within normal circuit specifications. To create reliable and repeatable PUF, the design must emphasize uniqueness while suppressing systematic patterns, digitizing noise, and environmental influences. As a practical example, we will explain the operation of a basic, challengeable, multiplexer-array PUF, explore its response characteristics, choose an operational threshold, and determine its nominal error rates.