446 research outputs found
Multiple observations for secret-key binding with SRAM PUFs
We present a new Multiple-Observations (MO) helper data scheme for secret-key binding to an SRAM-PUF. This MO scheme binds a single key to multiple enrollment observations of the SRAM-PUF. Performance is improved in comparison to classic schemes which generate helper data based on a single enrollment observation. The performance increase can be explained by the fact that the reliabilities of the different SRAM cells are modeled (implicitly) in the helper data. We prove that the scheme achieves secret-key capacity for any number of enrollment observations, and, therefore, it is optimal. We evaluate performance of the scheme using Monte Carlo simulations, where an off-the-shelf LDPC code is used to implement the linear error-correcting code. Another scheme that models the reliabilities of the SRAM cells is the so-called Soft-Decision (SD) helper data scheme. The SD scheme considers the one-probabilities of the SRAM cells as an input, which in practice are not observable. We present a new strategy for the SD scheme that considers the binary SRAM-PUF observations as an input instead and show that the new strategy is optimal and achieves the same reconstruction performance as the MO scheme. Finally, we present a variation on the MO helper data scheme that updates the helper data sequentially after each successful reconstruction of the key. As a result, the error-correcting performance of the scheme is improved over time
Probabilistic Shaping for Finite Blocklengths: Distribution Matching and Sphere Shaping
In this paper, we provide for the first time a systematic comparison of
distribution matching (DM) and sphere shaping (SpSh) algorithms for short
blocklength probabilistic amplitude shaping. For asymptotically large
blocklengths, constant composition distribution matching (CCDM) is known to
generate the target capacity-achieving distribution. As the blocklength
decreases, however, the resulting rate loss diminishes the efficiency of CCDM.
We claim that for such short blocklengths and over the additive white Gaussian
channel (AWGN), the objective of shaping should be reformulated as obtaining
the most energy-efficient signal space for a given rate (rather than matching
distributions). In light of this interpretation, multiset-partition DM (MPDM),
enumerative sphere shaping (ESS) and shell mapping (SM), are reviewed as
energy-efficient shaping techniques. Numerical results show that MPDM and SpSh
have smaller rate losses than CCDM. SpSh--whose sole objective is to maximize
the energy efficiency--is shown to have the minimum rate loss amongst all. We
provide simulation results of the end-to-end decoding performance showing that
up to 1 dB improvement in power efficiency over uniform signaling can be
obtained with MPDM and SpSh at blocklengths around 200. Finally, we present a
discussion on the complexity of these algorithms from the perspective of
latency, storage and computations.Comment: 18 pages, 10 figure
Partial Enumerative Sphere Shaping
The dependency between the Gaussianity of the input distribution for the
additive white Gaussian noise (AWGN) channel and the gap-to-capacity is
discussed. We show that a set of particular approximations to the
Maxwell-Boltzmann (MB) distribution virtually closes most of the shaping gap.
We relate these symbol-level distributions to bit-level distributions, and
demonstrate that they correspond to keeping some of the amplitude bit-levels
uniform and independent of the others. Then we propose partial enumerative
sphere shaping (P-ESS) to realize such distributions in the probabilistic
amplitude shaping (PAS) framework. Simulations over the AWGN channel exhibit
that shaping 2 amplitude bits of 16-ASK have almost the same performance as
shaping 3 bits, which is 1.3 dB more power-efficient than uniform signaling at
a rate of 3 bit/symbol. In this way, required storage and computational
complexity of shaping are reduced by factors of 6 and 3, respectively.Comment: 6 pages, 6 figure
Efficient key generation scheme for SRAM-PUFs using polar codes
Physical unclonable functions (PUFs) are a new promising means to realize cryptographic scenarios such as identification, authentication and secret key generation. PUFs avoid the need for key storage, because the device-unique randomness can be translated into a cryptographic key. SRAM-PUFs enjoy the properties that, while being easily evaluated (after a device power-up), they are unique, reproducible, physically unclonable and unpredictable. Error correction codes (ECCs) are essential blocks of secret-generation schemes, since PUF observations are always effected by noise and environmental changes. In this paper, we propose practical error correction schemes for PUF-based secret generation that are based on polar codes. The proposed scheme could generate a 128-bit key or 256-bit key using less PUF bits and helper data bits than before and achieve a low failure probability for a practical SRAM-PUFs application with error probability between 15% and 25%. Therefore SRAM-PUFs are considered to combine very well with authentication and unique cryptographic key generation for resource constrained devices
Information Theoretical Analysis of Identification based on Active Content Fingerprinting
Content fingerprinting and digital watermarking are techniques that are used
for content protection and distribution monitoring. Over the past few years,
both techniques have been well studied and their shortcomings understood.
Recently, a new content fingerprinting scheme called {\em active content
fingerprinting} was introduced to overcome these shortcomings. Active content
fingerprinting aims to modify a content to extract robuster fingerprints than
the conventional content fingerprinting. Moreover, contrary to digital
watermarking, active content fingerprinting does not embed any message
independent of contents thus does not face host interference. The main goal of
this paper is to analyze fundamental limits of active content fingerprinting in
an information theoretical framework.Comment: 35th WIC Symposium on Information Theory in the Benelu
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