Leveraging Distributions in Physical Unclonable Functions

Wenjie Che,Fareena Saqib,Jim Plusquellic,Venkata Kajuluri

doi:10.3390/cryptography1030017

Wenjie Che, Fareena Saqib + Show 2 more

Open Access

https://doi.org/10.3390/cryptography1030017

Copy DOI

Abstract

A special class of Physical Unclonable Functions (PUFs) referred to as strong PUFs can be used in novel hardware-based authentication protocols. Strong PUFs are required for authentication because the bit strings and helper data are transmitted openly by the token to the verifier, and therefore are revealed to the adversary. This enables the adversary to carry out attacks against the token by systematically applying challenges and obtaining responses in an attempt to machine learn, and later predict, the token’s response to an arbitrary challenge. Therefore, strong PUFs must both provide an exponentially large challenge space and be resistant to machine-learning attacks in order to be considered secure. We investigate a transformation called temperature–voltage compensation (TVCOMP), which is used within the Hardware-Embedded Delay PUF (HELP) bit string generation algorithm. TVCOMP increases the diversity and unpredictability of the challenge–response space, and therefore increases resistance to model-building attacks. HELP leverages within-die variations in path delays as a source of random information. TVCOMP is a linear transformation designed specifically for dealing with changes in delay introduced by adverse temperature–voltage (environmental) variations. In this paper, we show that TVCOMP also increases entropy and expands the challenge–response space dramatically.

Highlights

A Physical Unclonable Function (PUF) is a next-generation hardware security primitive
We construct a set of PN distributions using a specialized process that enables a systematic evaluation of the distribution effect
The fixed number of data sets constructed by our process represents only a small sample from this exponential space

Summary

Introduction

A Physical Unclonable Function (PUF) is a next-generation hardware security primitive. Security protocols such as authentication and encryption can leverage the random bit string and key generation capabilities of PUFs as a means of hardening vulnerable mobile and embedded devices against adversarial attacks. Authentication is a process that is carried out between a hardware token (smart card) and a verifier (a secure server at a bank) that is designed to confirm the identities of one or both parties [1]. Conventional methods of authentication that use area-heavy cryptographic primitives and non-volatile memory (NVM) are less attractive for these types of evolving embedded applications [2]. The special class of strong PUFs can further reduce area and energy overheads by eliminating cryptographic primitives that would otherwise be required

Methods

Results

Conclusion