78 research outputs found
Physical Layer Secret Key Agreement Using One-Bit Quantization and Low-Density Parity-Check Codes
Physical layer approaches for generating secret encryption keys for wireless systems using channel information have attracted increased interest from researchers in recent years. This paper presents a new approach for calculating log-likelihood ratios (LLRs) for secret key generation that is based on one-bit quantization of channel measurements and the difference between channel estimates at legitimate reciprocal nodes. The studied secret key agreement approach, which implements advantage distillation along with information reconciliation using Slepian-Wolf low-density parity-check (LDPC) codes, is discussed and illustrated with numerical results obtained from simulations. These results show the probability of bit disagreement for keys generated using the proposed LLR calculations compared with alternative LLR calculation methods for key generation based on channel state information. The proposed LLR calculations are shown to be an improvement to the studied approach of physical layer secret key agreement
Physical Layer Secret Key Agreement Using One-Bit Quantization and Low-Density Parity-Check Codes
Physical layer approaches for generating secret encryption keys for wireless
systems using channel information have attracted increased interest from
researchers in recent years. This paper presents a new approach for calculating
log-likelihood ratios (LLRs) for secret key generation that is based on one-bit
quantization of channel measurements and the difference between channel
estimates at legitimate reciprocal nodes. The studied secret key agreement
approach, which implements advantage distillation along with information
reconciliation using Slepian-Wolf low-density parity-check (LDPC) codes, is
discussed and illustrated with numerical results obtained from simulations.
These results show the probability of bit disagreement for keys generated using
the proposed LLR calculations compared with alternative LLR calculation methods
for key generation based on channel state information. The proposed LLR
calculations are shown to be an improvement to the studied approach of physical
layer secret key agreement.Comment: Officially Published on ODU Digital Commons at
https://digitalcommons.odu.edu/ece_etds/1
Multi-factor Physical Layer Security Authentication in Short Blocklength Communication
Lightweight and low latency security schemes at the physical layer that have
recently attracted a lot of attention include: (i) physical unclonable
functions (PUFs), (ii) localization based authentication, and, (iii) secret key
generation (SKG) from wireless fading coefficients. In this paper, we focus on
short blocklengths and propose a fast, privacy preserving, multi-factor
authentication protocol that uniquely combines PUFs, proximity estimation and
SKG. We focus on delay constrained applications and demonstrate the performance
of the SKG scheme in the short blocklength by providing a numerical comparison
of three families of channel codes, including half rate low density parity
check codes (LDPC), Bose Chaudhuri Hocquenghem (BCH), and, Polar Slepian Wolf
codes for n=512, 1024. The SKG keys are incorporated in a zero-round-trip-time
resumption protocol for fast re-authentication. All schemes of the proposed
mutual authentication protocol are shown to be secure through formal proofs
using Burrows, Abadi and Needham (BAN) and Mao and Boyd (MB) logic as well as
the Tamarin-prover
Exploiting Channel Diversity in Secret Key Generation from Multipath Fading Randomness
We design and analyze a method to extract secret keys from the randomness
inherent to wireless channels. We study a channel model for multipath wireless
channel and exploit the channel diversity in generating secret key bits. We
compare the key extraction methods based both on entire channel state
information (CSI) and on single channel parameter such as the received signal
strength indicators (RSSI). Due to the reduction in the degree-of-freedom when
going from CSI to RSSI, the rate of key extraction based on CSI is far higher
than that based on RSSI. This suggests that exploiting channel diversity and
making CSI information available to higher layers would greatly benefit the
secret key generation. We propose a key generation system based on low-density
parity-check (LDPC) codes and describe the design and performance of two
systems: one based on binary LDPC codes and the other (useful at higher
signal-to-noise ratios) based on four-ary LDPC codes
Coexistence and Secure Communication in Wireless Networks
In a wireless system, transmitted electromagnetic waves can propagate in all directions and can be received by other users in the system. The signals received by unintended receivers pose two problems; increased interference causing lower system throughput or successful decoding of the information which removes secrecy of the communication. Radio frequency spectrum is a scarce resource and it is allocated by technologies already in use. As a result, many communication systems use the spectrum opportunistically whenever it is available in cognitive radio setting or use unlicensed bands. Hence, efficient use of spectrum by sharing users is crucial to increase maximize system throughput. In addition, secrecy of a wireless communication system is traditionally provided by computational complexity of cryptography techniques employed. However, cryptography systems depend on either a random secret key generation mechanism or a trusted key distribution system. Recent developments in the wireless communication area provided a solution to both key generation and distribution problem via exploiting randomness of the wireless channel unconditional to the computational complexity.
In this dissertation, we propose solutions to the problems discussed. For spectrum sharing, we present a detailed analysis of challenges of efficient spectrum sharing without a central enforcing mechanism, provide insight to already existing power control algorithms and propose a novel non-greedy power allocation algorithm. Numerical simulations show that the proposed algorithm increases system throughput more than greedy algorithms and can use available spectrum to the fullest, yet it is robust to the presence of greedy users. For secrecy, we propose a practical and fast system for random secret key generation and reconciliation. We extend the proposed system to multiple-input-multiple-output systems and increase security via role reversal of the nodes while making it quicker by pre-encoding procedure. Information theory calculation and numerical simulations demonstrates that the proposed system provides a secure channel for legitimate users in the presence of a passive eavesdropper
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
On Enhancements of Physical Layer Secret Key Generation and Its Application in Wireless Communication Systems
As an alternative and appealing approach to providing information security in wireless communication systems, secret key generation at physical layer has demonstrated its potential in terms of efficiency and reliability over traditional cryptographic methods. Without the necessity of a management centre for key distribution or reliance on computational complexity, physical layer key generation protocols enable two wireless entities to extract identical and dynamic keys from the randomness of the wireless channels associated with them.
In this thesis, the reliability of secret key generation at the physical layer is examined in practical wireless channels with imperfect channel state information (CSI). Theoretical analyses are provided to relate key match rate with channel\u27s signal-to-noise ratio (SNR), degrees of channel reciprocity, and iterations of information reconciliation.
In order to increase key match rate of physical layer secret key generation, improved schemes in the steps of channel estimation and sample quantization are proposed respectively. In the channel estimation step, multiple observations of the wireless channels are integrated with a linear processor to provide a synthesized and more accurate estimation of the wireless channel. In the sample quantization step, a magnitude based quantization method with two thresholds is proposed to quantize partial samples, where specific quantization areas are selected to reduce cross-over errors. Significant improvements in key match rate are proven for both schemes in theoretical analysis and numerical simulations. Key match rate can even achieve 100% in both schemes with the assistance of information reconciliation process.
In the end, a practical application of physical layer secret key generation is presented, where dynamic keys extracted from the wireless channels are utilized for securing secret data transmission and providing efficient access control
A Critical Review of Physical Layer Security in Wireless Networking
Wireless networking has kept evolving with additional features and increasing capacity. Meanwhile, inherent characteristics of wireless networking make it more vulnerable than wired networks. In this thesis we present an extensive and comprehensive review of physical layer security in wireless networking. Different from cryptography, physical layer security, emerging from the information theoretic assessment of secrecy, could leverage the properties of wireless channel for security purpose, by either enabling secret communication without the need of keys, or facilitating the key agreement process. Hence we categorize existing literature into two main branches, namely keyless security and key-based security. We elaborate the evolution of this area from the early theoretic works on the wiretap channel, to its generalizations to more complicated scenarios including multiple-user, multiple-access and multiple-antenna systems, and introduce not only theoretical results but practical implementations. We critically and systematically examine the existing knowledge by analyzing the fundamental mechanics for each approach. Hence we are able to highlight advantages and limitations of proposed techniques, as well their interrelations, and bring insights into future developments of this area
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