PUF ROKs: a hardware approach to read-once keys

Abstract

Cryptographers have proposed the notion of read-once keys (ROKs) as a beneficial tool for a number of applications, such as delegation of authority. The premise of ROKs is that the key is destroyed by the process of reading it, thus preventing subsequent accesses. While the idea and the applications are well-understood, the consensus among cryptographers is that ROKs cannot be produced by algorithmic processes alone. Rather, a trusted hardware mechanism is needed to support the destruction of the key. In this work, we propose one such approach for using a hardware design to generate ROKs. Our approach is an application of physically unclonable functions (PUFs). PUFs use the intrinsic differences in hardware behavior to produce a random function that is unique to that hardware instance. Our design consists of incorporating the PUF in a feedback loop to make reading the key multiple times physically impossible.