893 research outputs found
To Harvest and Jam: A Paradigm of Self-Sustaining Friendly Jammers for Secure AF Relaying
This paper studies the use of multi-antenna harvest-and-jam (HJ) helpers in a
multi-antenna amplify-and-forward (AF) relay wiretap channel assuming that the
direct link between the source and destination is broken. Our objective is to
maximize the secrecy rate at the destination subject to the transmit power
constraints of the AF relay and the HJ helpers. In the case of perfect channel
state information (CSI), the joint optimization of the artificial noise (AN)
covariance matrix for cooperative jamming and the AF beamforming matrix is
studied using semi-definite relaxation (SDR) which is tight, while suboptimal
solutions are also devised with lower complexity. For the imperfect CSI case,
we provide the equivalent reformulation of the worst-case robust optimization
to maximize the minimum achievable secrecy rate. Inspired by the optimal
solution to the case of perfect CSI, a suboptimal robust scheme is proposed
striking a good tradeoff between complexity and performance. Finally, numerical
results for various settings are provided to evaluate the proposed schemes.Comment: 16 pages (double column), 8 figures, submitted for possible journal
publicatio
Vulnerability analysis of satellite-based synchronized smart grids monitoring systems
The large-scale deployment of wide-area monitoring systems could play a strategic role in supporting the evolution of traditional power systems toward smarter and self-healing grids. The correct operation of these synchronized monitoring systems requires a common and accurate timing reference usually provided by a satellite-based global positioning system. Although these satellites signals provide timing accuracy that easily exceeds the needs of the power industry, they are extremely vulnerable to radio frequency interference. Consequently, a comprehensive analysis aimed at identifying their potential vulnerabilities is of paramount importance for correct and safe wide-area monitoring system operation. Armed with such a vision, this article presents and discusses the results of an experimental analysis aimed at characterizing the vulnerability of global positioning system based wide-area monitoring systems to external interferences. The article outlines the potential strategies that could be adopted to protect global positioning system receivers from external cyber-attacks and proposes decentralized defense strategies based on self-organizing sensor networks aimed at assuring correct time synchronization in the presence of external attacks
Generative AI-aided Joint Training-free Secure Semantic Communications via Multi-modal Prompts
Semantic communication (SemCom) holds promise for reducing network resource
consumption while achieving the communications goal. However, the computational
overheads in jointly training semantic encoders and decoders-and the subsequent
deployment in network devices-are overlooked. Recent advances in Generative
artificial intelligence (GAI) offer a potential solution. The robust learning
abilities of GAI models indicate that semantic decoders can reconstruct source
messages using a limited amount of semantic information, e.g., prompts, without
joint training with the semantic encoder. A notable challenge, however, is the
instability introduced by GAI's diverse generation ability. This instability,
evident in outputs like text-generated images, limits the direct application of
GAI in scenarios demanding accurate message recovery, such as face image
transmission. To solve the above problems, this paper proposes a GAI-aided
SemCom system with multi-model prompts for accurate content decoding. Moreover,
in response to security concerns, we introduce the application of covert
communications aided by a friendly jammer. The system jointly optimizes the
diffusion step, jamming, and transmitting power with the aid of the generative
diffusion models, enabling successful and secure transmission of the source
messages
Impact Assessment of Hypothesized Cyberattacks on Interconnected Bulk Power Systems
The first-ever Ukraine cyberattack on power grid has proven its devastation
by hacking into their critical cyber assets. With administrative privileges
accessing substation networks/local control centers, one intelligent way of
coordinated cyberattacks is to execute a series of disruptive switching
executions on multiple substations using compromised supervisory control and
data acquisition (SCADA) systems. These actions can cause significant impacts
to an interconnected power grid. Unlike the previous power blackouts, such
high-impact initiating events can aggravate operating conditions, initiating
instability that may lead to system-wide cascading failure. A systemic
evaluation of "nightmare" scenarios is highly desirable for asset owners to
manage and prioritize the maintenance and investment in protecting their
cyberinfrastructure. This survey paper is a conceptual expansion of real-time
monitoring, anomaly detection, impact analyses, and mitigation (RAIM) framework
that emphasizes on the resulting impacts, both on steady-state and dynamic
aspects of power system stability. Hypothetically, we associate the
combinatorial analyses of steady state on substations/components outages and
dynamics of the sequential switching orders as part of the permutation. The
expanded framework includes (1) critical/noncritical combination verification,
(2) cascade confirmation, and (3) combination re-evaluation. This paper ends
with a discussion of the open issues for metrics and future design pertaining
the impact quantification of cyber-related contingencies
Security wireless sensor networks: prospects, challenges, and future
With the advancements of networking technologies and miniaturization of electronic devices, wireless sensor network (WSN) has become an emerging area of research in academic, industrial, and defense sectors. Different types of sensing technologies combined with processing power and wireless communication capability make sensor networks very lucrative for their abundant use in near future. However, many issues are yet to be solved before their full-scale practical implementations. Among all the research issues in WSN, security is one of the most challenging topics to deal with. The major hurdle of securing a WSN is imposed by the limited resources of the sensors participating in the network. Again, the reliance on wireless communication technology opens the door for various types of security threats and attacks. Considering the special features of this type of network, in this chapter we address the critical security issues in wireless sensor networks. We talk about cryptography, steganography, and other basics of network security and their applicability in WSN. We explore various types of threats and attacks against wireless sensor networks, possible countermeasures, mentionable works done so far, other research issues, etc. We also introduce the view of holistic security and future trends towards research in wireless sensor network security
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