An Easy-to-Design PUF Based on a Single Oscillator: The Loop PUF

Abstract

Abstract-This paper presents an easy to design Physically Unclonable Function (PUF). The proposed PUF implementation is a loop composed of N identical and controllable delay chains which are serially assembled in a loop to create a single ring oscillator. The frequency discrepancies resulting from the oscillator driven by complementary combinations of the delay chains allows to characterize one device. The presented PUF, nicknamed the Loop PUF (LPUF), returns a frequency comparison of loops made of N delay chains (N ≥ 2). The comparisons are done sequentially on the same structure. Unlike others PUFs based on delays, there is no specific routing constraints. Hence the LPUF is particularly flexible and easy to design. The basic use of the Loop PUF is to generate intrinsic device keys for cryptographic algorithms. It can also be used to generate challenge response pairs for simple authentication. Experiments have been carried out on CYCLONE II FPGAs to assess the performance of the LPUF, such as randomness, uniqueness and steadiness. They clearly show both the easiness of design and the quality level of the LPUF. The measurement time vs steadiness, as well as resistance against side-channel and modeling attacks are discussed.

Implementation and Analysis of Ring Oscillator PUFs on 60 nm Altera Cyclone FPGAs

“…Bernard et al (2012) give no details of how they achieved the implementation of their RO PUF on Altera FPGAs. In Cherif, Danger, Guilley, and Bossuet (2012), another kind of delay-based PUF, called loop PUF, working with less gates than the RO PUF, is implemented for Altera FPGAs. They hint that "LogicLocks" and node location declarations were used, but no further details are given.…”

Disposable configuration of remotely reconfigurable systems

“…Most FPGA vendors suggest storing symmetric keys in a volatile memory area that requires external batteries [19] or one time programmable memory (anti-fuse) [19]. It is also possible to use a physical unclonable function (PUF like [28,29]) to generate and store keys, but these functions must be able to exchange their response (a PUF-ID) with the server before the configuration is encrypted [30]. Some academic works proposed a design for a trusted platform module (TPM) dedicated to FPGAs and reconfigurable architectures that can manage keys, and encrypt and decrypt the configuration, but that can also be used for cryptographic needs depending on the application [31,32].…”

Constructions of Optimal and Near-Optimal Multiply Constant-Weight Codes

“…, ⌊n 2 D(n 1 , 3, 2)⌋} for all n 1 , n 2 > 0 except for (n 1 , n 2 ) ∈ {(6, 5), (7,3), (7,4), (7,5)}, whose values are listed below.…”

“…Multiply constant-weight codes have attracted recent attention due to an application in the design of certain physically unclonable functions (PUFs) [1], [2], [5]. Introduced by Pappu et al [6], PUFs provide innovative low-cost authentication methods that are derived from complex physical characteristics of electronic devices and have recently become an attractive option to provide security in low cost devices such as RFIDs and smart cards [5]- [8].…”

“…Introduced by Pappu et al [6], PUFs provide innovative low-cost authentication methods that are derived from complex physical characteristics of electronic devices and have recently become an attractive option to provide security in low cost devices such as RFIDs and smart cards [5]- [8]. Reliability and implementation considerations on programmable circuits for the design of Loop PUFs [5] lead to the study of multiply constant-weight codes.…”