Improving the quality of a Physical Unclonable Function using configurable Ring Oscillators

Abstract

A silicon Physical Unclonable Function (PUF), which is a die-unique challenge-response function, is an emerging hardware primitive for secure applications. It exploits manufacturing process variations in a die to generate unique signatures out of a chip. This enables chip authentication and cryptographic key generation.A Ring Oscillator (RO) based PUF is a promising solution for FPGA platforms. However, the quality factors of this PUF, which include uniqueness, reliability and attack resiliency, are negatively affected by environmental noise and systematic variations in the die. This paper proposes two methods to address these negative effects, and to achieve a higher reliability in an RO-based PUF. Both methods are empirically verified on a population of five FPGAs over varying environmental conditions, and demonstrate how practically useful RO-based PUF can be achieved.

Hardware authentication based on PUFs and SHA-3 2^nd round candidates

“…They are shared avoiding unnecessary hardware duplication and power dissipation. The number of inverters per ring depends on the operation mode, being three in the case of nonce generation, and five [16] in the case of PUF operation. Ring oscillator blocks and the complete PUF-TRNG module are shown in Figure 4.…”

“…The idea is to compare the "right"couples of oscillators, that is, choosing those rings whose difference in frequency is reliable (the challenge is the variable that selects the couple). Using this approach, results in [16] show no variation of the PUF response with temperature, and a constant value of 4 unstable bits due to voltage variations (independently of the ring oscillators employed). This means that it is possible for ring oscillator PUFs to generate keys without using error correcting codes.…”

“…Instead of adding postprocessing, Maiti et al in [16] proposed to address the problem of noise when designing the PUF. The idea is to compare the "right"couples of oscillators, that is, choosing those rings whose difference in frequency is reliable (the challenge is the variable that selects the couple).…”

“…The PUF selected in this work is the structure proposed in [16]. The number of ring oscillators used is 33 to generate a 32 bit response.…”

A flexible design flow for software IP binding in commodity FPGA

“…However, for cryptographic operation, a stable key is necessary. Generating noise free keys from PUF is an active area of research, and several error correction schemes have been proposed such as [45]. Most of them require a complex implementation in software and/or hardware.…”