15 research outputs found
Low-complexity and Reliable Transforms for Physical Unclonable Functions
Noisy measurements of a physical unclonable function (PUF) are used to store
secret keys with reliability, security, privacy, and complexity constraints. A
new set of low-complexity and orthogonal transforms with no multiplication is
proposed to obtain bit-error probability results significantly better than all
methods previously proposed for key binding with PUFs. The uniqueness and
security performance of a transform selected from the proposed set is shown to
be close to optimal. An error-correction code with a low-complexity decoder and
a high code rate is shown to provide a block-error probability significantly
smaller than provided by previously proposed codes with the same or smaller
code rates.Comment: To appear in IEEE International Conference on Acoustics, Speech, and
Signal Processing 202
Functional mobile-based two-factor authentication by photonic physical unclonable functions
Given the rapid expansion of the Internet of Things and because of the concerns around counterfeited goods, secure and resilient cryptographic systems are in high demand. Due to the development of digital ecosystems, mobile applications for transactions require fast and
reliable methods to generate secure cryptographic keys, such as Physical Unclonable Functions (PUFs). We demonstrate a compact and
reliable photonic PUF device able to be applied in mobile-based authentication. A miniaturized, energy-efficient, and low-cost token was
forged of flexible luminescent organic–inorganic hybrid materials doped with lanthanides, displaying unique challenge–response pairs (CRPs)
for two-factor authentication. Under laser irradiation in the red spectral region, a speckle pattern is attained and accessed through conventional charge-coupled cameras, and under ultraviolet light-emitting diodes, it displays a luminescent pattern accessed through hyperspectral
imaging and converted to a random intensity-based pattern, ensuring the two-factor authentication. This methodology features the use of
a discrete cosine transform to enable a low-cost and semi-compact encryption system suited for speckle and luminescence-based CRPs.
The PUF evaluation and the authentication protocol required the analysis of multiple CRPs from different tokens, establishing an optimal
cryptographic key size (128 bits) and an optimal decision threshold level that minimizes the error probability.publishe
Secure and Reliable Key Agreement with Physical Unclonable Functions
Different transforms used in binding a secret key to correlated
physical-identifier outputs are compared. Decorrelation efficiency is the
metric used to determine transforms that give highly-uncorrelated outputs.
Scalar quantizers are applied to transform outputs to extract uniformly
distributed bit sequences to which secret keys are bound. A set of transforms
that perform well in terms of the decorrelation efficiency is applied to ring
oscillator (RO) outputs to improve the uniqueness and reliability of extracted
bit sequences, to reduce the hardware area and information leakage about the
key and RO outputs, and to maximize the secret-key length. Low-complexity
error-correction codes are proposed to illustrate two complete key-binding
systems with perfect secrecy, and better secret-key and privacy-leakage rates
than existing methods. A reference hardware implementation is also provided to
demonstrate that the transform-coding approach occupies a small hardware area.Comment: An extra term in the last page due to the mismatch between the Arxiv
compiler and MDPI template is eliminated. No other change
Implementação fotónica de funções fisicamente não clonáveis
This dissertation aimed to study and develop optical Physically
Unclonable Functions, which are physical devices characterized by
having random intrinsic variations, thus being eligible towards high security
systems due to their unclonability, uniqueness and randomness.
With the rapid expansion of technologies such as Internet of Things
and the concerns around counterfeited goods, secure and resilient
cryptographic systems are in high demand. Moreover the development
of digital ecosystems, mobile applications towards transactions now
require fast and reliable algorithms to generate secure cryptographic
keys. The statistical nature of speckle-based imaging creates an
opportunity for these cryptographic key generators to arise.
In the scope of this work, three different tokens were implemented
as physically unclonable devices: tracing paper, plastic optical fiber
and an organic-inorganic hybrid. These objects were subjected to
a visible light laser stimulus and produced a speckle pattern which
was then used to retrieve the cryptographic key associated to each
of the materials. The methodology deployed in this work features
the use of a Discrete Cosine Transform to enable a low-cost and
semi-compact 128-bit key encryption channel. Furthermore, the
authentication protocol required the analysis of multiple responses
from different samples, establishing an optimal decision threshold level
that maximized the robustness and minimized the fallibility of the
system. The attained 128-bit encryption system performed, across
all the samples, bellow the error probability detection limit of 10-12,
showing its potential as a cryptographic key generator.Nesta dissertação pretende-se estudar e desenvolver Funções Fisicamente
Não Clonáveis, dispositivos caracterizados por terem variações
aleatórias intrínsecas, sendo, portanto, elegíveis para sistemas de alta
segurança devido à sua impossibilidade de clonagem, unicidade e
aleatoriedade. Com a rápida expansão de tecnologias como a Internet
das Coisas e as preocupações com produtos falsificados, os sistemas
criptográficos seguros e resilientes são altamente requisitados.
Além disso, o desenvolvimento de ecossistemas digitais e de aplicações
móveis para transações comerciais requerem algoritmos rápidos e seguros
de geração de chaves criptográficas. A natureza estatística das
imagens baseadas no speckle cria uma oportunidade para o aparecimento
desses geradores de chaves criptográficas.
No contexto deste trabalho, três dispositivos diferentes foram implementados
como funções fisicamente não clonáveis, nomeadamente, papel
vegetal, fibra ótica de plástico e um híbrido orgânico-inorgânico.
Estes objetos foram submetidos a um estímulo de luz coerente na região
espectral visível e produziram um padrão de speckle o qual foi utilizado
para recuperar a chave criptográfica associada a cada um dos materiais.
A metodologia implementada neste trabalho incorpora a Transformada
Discreta de Cosseno, o que possibilita a criação de um sistema criptográfico de 128 bits caracterizado por ser semi-compacto e de baixo
custo. O protocolo de autenticação exigiu a análise de múltiplas respostas
de diferentes Physically Unclonable Functions (PUFs), o que
permitiu estabelecer um nível de limite de decisão ótimo de forma a
maximizar a robustez e minimizar a probabilidade de erro por parte
do sistema. O sistema de encriptação de 128 bits atingiu valores de
probabilidade de erro abaixo do limite de deteção, 10-12, para todas
as amostras, mostrando o seu potencial como gerador de chaves criptográficas.Mestrado em Engenharia Físic
Variable-Length Bit Mapping and Error-Correcting Codes for Higher-Order Alphabet PUFs
Device-specific physical characteristics provide the foundation for PUFs, a hardware primitive for secure storage of cryptographic keys. So far, they have been implemented by either directly evaluating a binary output or by mapping outputs from a higher-order alphabet to a fixed-length bit sequence. However, the latter causes a significant bias in the derived key when combined with an equidistant quantization.
To overcome this limitation, we propose a variable-length bit mapping that reflects the properties of a Gray code in a different metric, namely the Levenshtein metric instead of the classical Hamming metric. Subsequent error-correction is therefore based on a custom insertion/deletion correcting code. This new approach effectively counteracts the bias in the derived key already at the input side.
We present the concept for our scheme and demonstrate its feasibility based on an empirical PUF distribution. As a result, we increase the effective output bit length of the secret by over 40% compared to state-of-the-art approaches while at the same time obtaining additional advantages, e.g., an improved tamper-sensitivity. This opens up a new direction of Error-Correcting Codes (ECCs) for PUFs that output responses with symbols of higher-order output alphabets
Biometric and Physical Identifiers with Correlated Noise for Controllable Private Authentication
The problem of secret-key based authentication under privacy and storage
constraints on the source sequence is considered. The identifier measurement
channels during authentication are assumed to be controllable via a
cost-constrained action sequence. Single-letter inner and outer bounds for the
key-leakage-storage-cost regions are derived for a generalization of a classic
two-terminal key agreement model with an eavesdropper that observes a sequence
that is correlated with the sequences observed by the legitimate terminals. The
additions to the model are that the encoder observes a noisy version of a
remote source, and the noisy output and the remote source output together with
an action sequence are given as inputs to the measurement channel at the
decoder. Thus, correlation is introduced between the noise components on the
encoder and decoder measurements. The model with a secret key generated by an
encoder is extended to the randomized models, where a secret-key is embedded to
the encoder. The results are relevant for several user and device
authentication scenarios including physical and biometric identifiers with
multiple measurements that provide diversity and multiplexing gains. To
illustrate the behavior of the rate region, achievable (secret-key rate,
storage-rate, cost) tuples are given for binary identifiers and measurement
channels that can be represented as a mixture of binary symmetric subchannels.
The gains from using an action sequence such as a large secret-key rate at a
significantly small hardware cost, are illustrated to motivate the use of
low-complexity transform-coding algorithms with cost-constrained actions.Comment: Shorter version to appear in the IEEE International Symposium on
Information Theory 202
Reflective-Physically Unclonable Function based System for Anti-Counterfeiting
Physically unclonable functions (PUF) are physical security mechanisms, which utilize inherent randomness in processes used to instantiate physical objects. In this dissertation, an extensive overview of the state of the art in implementations, accompanying definitions and their analysis is provided. The concept of the reflective-PUF is presented as a product security solution. The viability of the concept, its evaluation and the requirements of such a system is explored