Silicon Physical Unclonable Function Research Articles

A Survey on Silicon PUFs and Recent Advances in Ring Oscillator PUFs

Silicon physical unclonable function (PUF) is a popular hardware security primitive that exploits the intrinsic variation of IC manufacturing process to generate chip-unique information for various security related applications. For example, the PUF information can be used as a chip identifier, a secret key, the seed for a random number generator, or the response to a given challenge. Due to the unpredictability and irreplicability of IC manufacturing variation, silicon PUF has emerged as a promising hardware security primitive and gained a lot of attention over the past few years. In this article, we first give a survey on the current state-of-the-art of silicon PUFs, then analyze known attacks to PUFs and the countermeasures. After that we discuss PUF-based applications, highlight some recent research advances in ring oscillator PUFs, and conclude with some challenges and opportunities in PUF research and applications.

Obtaining Statistically Random Information From Silicon Physical Unclonable Functions

Silicon physical unclonable functions (PUFs) utilize the variation during silicon fabrication process to extract information that will be unique for each chip. There have been many recent approaches to how PUF can be used to improve security-related applications. However, it is well known that the fabrication variation has very strong spatial correlation<;xref rid="fn1" ref-type="fn"><;sup>1<;/sup><;/xref> and this has been pointed out as a security threat to silicon PUF. In fact, when we apply NIST's statistical test suite for randomness against the random sequences generated from a population of 125 ring oscillator PUFs using classic 1-out-of-8 coding and neighbor coding, none of them can pass all the tests. In this paper, we propose to decouple the unwanted systematic variation from the desired random variation through a regression-based distiller, where the basic idea is to build a model for the systematic variation so we can generate the random sequences only from the true random variation. Applying neighbor coding to the same benchmark data, our experiment shows that second- and third-order polynomials distill random sequences that pass all the NIST randomness tests. So does fourth-order polynomial in the case of 1-out-of-8 coding. Finally, we introduce two generic random sequence generation methods. The sequences they generate fail all the randomness tests, but with the help of our proposed polynomial distiller, all but one tests are passed. These results demonstrate that our method can provide statistically random PUF information and thus bolster the security characteristics of existing PUF schemes.<;fn id="fn1"><;label><;sup>1<;/sup><;/label><;p>Spatial correlations and systematic fabrication variations referred hereafter are different for each PUF.

A PUF Based on a Transient Effect Ring Oscillator and Insensitive to Locking Phenomenon

This paper presents a new silicon physical unclonable function (PUF) based on a transient effect ring oscillator (TERO). The proposed PUF has state of the art PUF characteristics with a good ratio of PUF response variability to response length. Unlike RO-PUF, it is not sensitive to the locking phenomenon, which challenges the use of ring oscillators for the design of both PUF and TRNG. The novel architecture using differential structures guarantees high stability of the TERO-PUF. The area of the TERO-PUF is relatively high, but is still comparable with other PUF designs. However, since the same piece of hardware can be used for both PUF and random number generation, the proposed principle offers an interesting low area mixed solution.

Hardware-Anchored Security Based on SRAM PUFs, Part 1

Physical unclonable functions (PUFs) originate in intrinsic properties extracted from devices and objects for the purpose of identification. A special type of silicon PUFs called SRAM (static RAM) PUFs can help make integrated circuits securer.

High Uniqueness Arbiter-Based PUF Circuit Utilizing RG-DTM Scheme for Identification and Authentication Applications

Silicon Physical Unclonable Functions (PUFs) have been proposed to exploit inherent characteristics caused by process variations, such as transistor size, threshold voltage and so on, and to produce an inexpensive and tamper-resistant device such as IC identification, authentication and key generation. We have focused on the arbiter-PUF utilizing the relative delay-time difference between the equivalent paths. The conventional arbiter-PUF has a technical issue, which is low uniqueness caused by the ununiformity on response-generation. To enhance the uniqueness, a novel arbiter-based PUF utilizing the Response Generation according to the Delay Time Measurement (RG-DTM) scheme, has been proposed. In the conventional arbiter-PUF, the response 0 or 1 is assigned according to the single threshold of relative delay-time difference. On the contrary, the response 0 or 1 is assigned according to the multiple threshold of relative delay-time difference in the RG-DTM PUF. The conventional and RG-DTM PUF were designed and fabricated with 0.18µm CMOS technology. The Hamming distances (HDs) between different chips, which indicate the uniqueness, were calculated by 256-bit responses from the identical challenges on each chip. The ideal distribution of HDs, which indicates high uniqueness, is achieved in the RG-DTM PUF using 16 thresholds of relative delay-time differences. The generative stability, which is the fluctuation of responses in the same environment, and the environmental stability, which is the changes of responses in the different environment were also evaluated. There is a trade-off between high uniqueness and high stability, however, the experimental data shows that the RG-DTM PUF has extremely smaller false matching probability in the identification compared to the conventional PUF.

A RFID Privacy Protocol Based on PUF

Physical Unclonable Function (PUF) is an excellent choice for key management in security domain. A Silicon PUF based RFID privacy protocol is proposed. Unlike general PUF applications which apply PUF in the tag-end, we employ PUF within a reader. Challenge -Responding Pairs (CRPs) on PUF in the proposal are reusable. Tag’s data structure is designed to a three level stack. Each level of the stack stands for a privacy state of the tag. State changing needs a password which only be transferred with plaintext. Password produce, storage, input/output operations are program control. We take a supermarket as application scene.