238 research outputs found
Key Generation in Wireless Sensor Networks Based on Frequency-selective Channels - Design, Implementation, and Analysis
Key management in wireless sensor networks faces several new challenges. The
scale, resource limitations, and new threats such as node capture necessitate
the use of an on-line key generation by the nodes themselves. However, the cost
of such schemes is high since their secrecy is based on computational
complexity. Recently, several research contributions justified that the
wireless channel itself can be used to generate information-theoretic secure
keys. By exchanging sampling messages during movement, a bit string can be
derived that is only known to the involved entities. Yet, movement is not the
only possibility to generate randomness. The channel response is also strongly
dependent on the frequency of the transmitted signal. In our work, we introduce
a protocol for key generation based on the frequency-selectivity of channel
fading. The practical advantage of this approach is that we do not require node
movement. Thus, the frequent case of a sensor network with static motes is
supported. Furthermore, the error correction property of the protocol mitigates
the effects of measurement errors and other temporal effects, giving rise to an
agreement rate of over 97%. We show the applicability of our protocol by
implementing it on MICAz motes, and evaluate its robustness and secrecy through
experiments and analysis.Comment: Submitted to IEEE Transactions on Dependable and Secure Computin
A Survey of Physical Layer Security Techniques for 5G Wireless Networks and Challenges Ahead
Physical layer security which safeguards data confidentiality based on the
information-theoretic approaches has received significant research interest
recently. The key idea behind physical layer security is to utilize the
intrinsic randomness of the transmission channel to guarantee the security in
physical layer. The evolution towards 5G wireless communications poses new
challenges for physical layer security research. This paper provides a latest
survey of the physical layer security research on various promising 5G
technologies, including physical layer security coding, massive multiple-input
multiple-output, millimeter wave communications, heterogeneous networks,
non-orthogonal multiple access, full duplex technology, etc. Technical
challenges which remain unresolved at the time of writing are summarized and
the future trends of physical layer security in 5G and beyond are discussed.Comment: To appear in IEEE Journal on Selected Areas in Communication
Reconfigurable Intelligent Surface-Assisted Secret Key Generation in Spatially Correlated Channels
Reconfigurable intelligent surface (RIS) is a disruptive technology to
enhance the performance of physical-layer key generation (PKG) thanks to its
ability to smartly customize the radio environments. Existing RIS-assisted PKG
methods are mainly based on the idealistic assumption of an independent and
identically distributed (i.i.d.) channel model at both the base station (BS)
and the RIS. However, the i.i.d. model is inaccurate for a typical RIS in an
isotropic scattering environment and neglecting the existence of channel
spatial correlation would possibly degrade the PKG performance. In this paper,
we establish a general spatially correlated channel model and propose a new
channel probing framework based on the transmit and the reflective beamforming.
We derive a closed-form key generation rate (KGR) expression and formulate an
optimization problem, which is solved by using the low-complexity Block
Successive Upper-bound Minimization (BSUM) with Mirror-Prox method. Simulation
results show that compared to the existing methods based on the i.i.d. fading
model, our proposed method achieves about dB transmit power gain when the
spacing between two neighboring RIS elements is a quarter of the wavelength.
Also, the KGR increases significantly with the number of RIS elements while
that increases marginally with the number of BS antennas.Comment: arXiv admin note: text overlap with arXiv:2207.1175
Sparse Signal Processing Concepts for Efficient 5G System Design
As it becomes increasingly apparent that 4G will not be able to meet the
emerging demands of future mobile communication systems, the question what
could make up a 5G system, what are the crucial challenges and what are the key
drivers is part of intensive, ongoing discussions. Partly due to the advent of
compressive sensing, methods that can optimally exploit sparsity in signals
have received tremendous attention in recent years. In this paper we will
describe a variety of scenarios in which signal sparsity arises naturally in 5G
wireless systems. Signal sparsity and the associated rich collection of tools
and algorithms will thus be a viable source for innovation in 5G wireless
system design. We will discribe applications of this sparse signal processing
paradigm in MIMO random access, cloud radio access networks, compressive
channel-source network coding, and embedded security. We will also emphasize
important open problem that may arise in 5G system design, for which sparsity
will potentially play a key role in their solution.Comment: 18 pages, 5 figures, accepted for publication in IEEE Acces
Lightweight Information Security Methods for Indoor Wireless Body Area Networks: from Channel Modeling to Secret Key Extraction
A group of wirelessly communicating sensors that are placed inside, on or around a human body constitute a Wireless Body Area Network (WBAN). Continuous monitoring of vital signs through WBANs have a potential to revolutionize current health care services by reducing the cost, improving accessibility, and facilitating medical diagnosis. However, sensitive nature of personal health data requires WBANs to integrate appropriate security methods and practices. As limited hardware resources make conventional security measures inadequate in a WBAN context, this work is focused on alternative techniques based on Wireless Physical Layer Security (WPLS). More specifically, we introduce a symbiosis of WPLS and Compressed Sensing to achieve security at the time of sampling. We successfully show how the proposed framework can be applied to electrocardiography data saving significant computational and memory resources. In the scenario when a WBAN Access Point can make use of diversity methods in the form of Switch-and-Stay Combining, we demonstrate that output Signal-to-Noise Ratio (SNR) and WPLS key extraction rate are optimized at different switching thresholds. Thus, the highest key rate may result in significant loss of output SNR. In addition, we also show that the past WBAN off-body channel models are insufficient when the user exhibits dynamic behavior. We propose a novel Rician based off-body channel model that can naturally reflect body motion by randomizing Rician factor K and considering small and large scale fading to be related. Another part of our investigation provides implications of user\u27s dynamic behavior on shared secret generation. In particular, we reveal that body shadowing causes negative correlation of the channel exposing legitimate participants to a security threat. This threat is analyzed from a qualitative and quantitative perspective of a practical secret key extraction algorithm
CSI-based versus RSS-based Secret-Key Generation under Correlated Eavesdropping
Physical-layer security (PLS) has the potential to strongly enhance the
overall system security as an alternative to or in combination with
conventional cryptographic primitives usually implemented at higher network
layers. Secret-key generation relying on wireless channel reciprocity is an
interesting solution as it can be efficiently implemented at the physical layer
of emerging wireless communication networks, while providing
information-theoretic security guarantees. In this paper, we investigate and
compare the secret-key capacity based on the sampling of the entire complex
channel state information (CSI) or only its envelope, the received signal
strength (RSS). Moreover, as opposed to previous works, we take into account
the fact that the eavesdropper's observations might be correlated and we
consider the high signal-to-noise ratio (SNR) regime where we can find simple
analytical expressions for the secret-key capacity. As already found in
previous works, we find that RSS-based secret-key generation is heavily
penalized as compared to CSI-based systems. At high SNR, we are able to
precisely and simply quantify this penalty: a halved pre-log factor and a
constant penalty of about 0.69 bit, which disappears as Eve's channel gets
highly correlated
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