Normalization and Multi-Valued Symbol Extraction From RO-PUFs for Enhanced Uniform Probability Distributions

In this paper, a coded modulation scheme employing signal shaping is proposed and designed for use in multi-valued physical unclonable functions (PUFs). In the literature, usually binary PUFs are considered, where less than one bit of entropy is extracted from each fundamental building block (PUF node). This randomness in the hardware may then used for the derivation of cryptographic keys. Meanwhile, PUFs over higher-order alphabets, so-called multi-valued PUFs (MVPUFs) have been presented. Typically, symbols from a higher-order alphabet are extracted by suited quantization. In contrast, in this paper we propose a coded modulation scheme which directly works on the analog values provided by the PUF nodes. We establish an interpretation as digital transmission with randomness at the transmitter, and thereon calculate the respective capacities of bit levels for the Gaussian distributed reference PUF readout in additive Gaussian noise. In addition, the metric for optimum soft-decision decoding is derived. Thereby, the coded modulation scheme can be designed for the present situation. A helper data scheme adapted to the given situation is proposed and analyzed. Moreover, on top of the multilevel coding scheme, we employ signal shaping for the first time in the context of PUFs. In particular, trellis shaping is applied. By this, the coded modulation scheme can be perfectly matched to the PUF statistics. This is reflected by the results of conducted numerical simulations. High coding rates can be used, i.e., a large entropy per PUF node can be extracted, with very high reliabilities.

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“…However, a similar match can be attained if the regions are defined such that they are used with equal probabilities, cf., e.g., [4], [20]. Fig.…”

Section: Uniform Signalingmentioning

confidence: 99%

“…As further method, [4] proposes to model the quantized symbols (alphabet of cardinality q) as a q-ary symmetric channel and to apply q-ary error-correcting code over the Hamming metric and over the Lee metric. In [20], equi-probable and discrete equi-probable quantization are applied and analyzed, while error correction is not treated.…”

Section: Introductionmentioning

confidence: 99%

Coded Modulation and Shaping for Multivalued Physical Unclonable Functions

Fischer

Müelich

2022

IEEE Access

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“…This paper focuses on multi-valued responses as they were applied in [9], where RO frequency comparisons are not used to generate single-but multibit responses, thus giving more entropy for the same hardware resources. All ROs that are placed in the same slice type are grouped together and their mean frequencies are divided into intervals, each interval representing one symbol.…”

Section: B Multi-valued Responsementioning

confidence: 99%

“…In the next step, the correction of temperature influences was evaluated for multi-valued symbols. In this paper eight different symbols were used as in [9] and thus a single RO can produce 3 bit of response. Therefore, for each RO its reference symbol S ref was extracted at room-temperature T 20 .…”

Section: B Symbol Correctionmentioning

confidence: 99%

Using Polynomial Interpolation for Reproducing Multi-Valued Responses of Physical Unclonable Functions on FPGAs

Mandry

Müelich

Becker

et al. 2021

2021 IEEE International Symposium on Circuits and Systems (ISCAS)

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A well-known problem when using Physical Unclonable Functions for secret key generation and storage, is the instability of PUF responses due to environmental conditions like temperature variations. Using Ring Oscillator PUFs (RO-PUFs), a response bit is usually derived based on the comparison of a RO frequency with either a threshold or another RO frequency. Especially for multi-valued PUFs it is of importance to decrease RO frequency errors before digitization. Otherwise, these errors can result in a huge amount of bit-flips. To counteract environmental influence in the reproduction phase, we propose to map a frequency, which might be remeasured under a temperature condition different from initialization, closer to the initial frequency by using a method based on polynomial interpolation. This paper presents how such an approach can decrease errors in multi-valued responses and evaluates the error based on the used polynomial order and thus complexity.

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“…For the PUF, it is required to generate the same response for the same challenge and generate a new response for each challenge. In literature, many architectures of PUFs have been proposed and implemented, such as Ring Oscillator PUF (RO-PUF) [6]- [9], Arbiter PUF [10], [11], Transient Effect Ring Oscillator PUF (TERO-PUF) [12]- [15], and SRAM PUF [16]- [19]. The Arbiter PUF is delaybased.…”

Section: Introductionmentioning

confidence: 99%

Ultra-Low Power Oscillator Collapse Physical Unclonable Function Based on FinFET

et al. 2021

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The main purpose of this paper is to achieve ultra-low power Physical Unclonable Function (PUF) to meet the requirements for Internet of Things (IoT) applications. PUFs are promising hardware security primitives that are based on the uniqueness and the unclonability of the device's physical characteristics to provide a unique identifier for devices. PUFs can be used in device authentication and for secure key storage and generation. This paper presents Oscillator Collapse Physical Unclonable Function (OC-PUF), which is suitable for low power applications. The power consumption is reduced based on designing the most power-hungry modules in the OC-PUF. An Oscillator Collapse (OC) is designed to work in the near-threshold voltage region, which reduces the power consumption. More power reduction is achieved by designing a new Collapse Time Comparator (CTC). Due to the process variations, the oscillations period of each OC is different. The CTC generates the output response bit by comparing the oscillations periods of the two selected OCs. The simulation results demonstrate that the proposed OC-PUF can effectively reduce the power consumption. The proposed PUF is designed using 20 nm triple gate FinFET technology. The Simulation results for 1000 different chips with the same input challenge, show that the average power is 140 nW, with the worst case being 740 nW. The best case is 63 nW per challenge-response pair at supply voltage 0.5 V. The averaged reliability of the OC-PUF is 99.8%, at temperatures from-40 to 125 • C and supply voltage 0.5 ± 10%. The proposed OC-PUF decreases the power consumption while retaining high-performance metrics. INDEX TERMS Authentication, hardware security, low power consumption, process variation, reliability, transient effect of ring oscillator.

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Normalization and Multi-Valued Symbol Extraction From RO-PUFs for Enhanced Uniform Probability Distributions

Cited by 14 publications

References 11 publications

Coded Modulation and Shaping for Multivalued Physical Unclonable Functions

Coded Modulation and Shaping for Multivalued Physical Unclonable Functions

Using Polynomial Interpolation for Reproducing Multi-Valued Responses of Physical Unclonable Functions on FPGAs

Ultra-Low Power Oscillator Collapse Physical Unclonable Function Based on FinFET

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