74 research outputs found
Throughput Optimal On-Line Algorithms for Advanced Resource Reservation in Ultra High-Speed Networks
Advanced channel reservation is emerging as an important feature of ultra
high-speed networks requiring the transfer of large files. Applications include
scientific data transfers and database backup. In this paper, we present two
new, on-line algorithms for advanced reservation, called BatchAll and BatchLim,
that are guaranteed to achieve optimal throughput performance, based on
multi-commodity flow arguments. Both algorithms are shown to have
polynomial-time complexity and provable bounds on the maximum delay for
1+epsilon bandwidth augmented networks. The BatchLim algorithm returns the
completion time of a connection immediately as a request is placed, but at the
expense of a slightly looser competitive ratio than that of BatchAll. We also
present a simple approach that limits the number of parallel paths used by the
algorithms while provably bounding the maximum reduction factor in the
transmission throughput. We show that, although the number of different paths
can be exponentially large, the actual number of paths needed to approximate
the flow is quite small and proportional to the number of edges in the network.
Simulations for a number of topologies show that, in practice, 3 to 5 parallel
paths are sufficient to achieve close to optimal performance. The performance
of the competitive algorithms are also compared to a greedy benchmark, both
through analysis and simulation.Comment: 9 pages, 8 figure
MULTI-PHOTON TOLERANT QUANTUM KEY DISTRIBUTION PROTOCOLS FOR SECURED GLOBAL COMMUNICATION
This dissertation investigates the potential of multi-photon tolerant protocols for satellite-aided global quantum key distribution (QKD). Recent investigations like braided single-stage protocol and the implementation of the three-stage protocol in fiber have indicated that multi-photon tolerant protocols have wide-ranging capabilities for increasing the distance and speed of quantum-secure communication. This dissertation proposes satellite-based network multicasting and its operation that can profitably use multi-photon tolerant protocols for quantum-secure global communication.
With a growingly interconnected world and an increasing need for security in communication, communication satellites at Lower Earth Orbits (LEO), Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO) have a potential role in serving as a means to distribute secure keys for encryption among distant endpoints. This dissertation systematically evaluates such a role. The dissertation proposes a layered framework using satellites and fiber optic links that can form a composite system for carrying the information payload and distributing quantum-secure keys for encrypting information in transit.
Quantum communications links are currently point-to-point. Considering the concept of global QKD network, there is need for multicast quantum links. Multi casting can be achieved in quantum networks by (a) using multiple wavelengths, or (b) using use specific set of bases. In efforts to develop a composite quantum secure global communication system; this dissertation also introduces the concept of multi-photon tolerant quantum threshold cryptography. The motivation for development of threshold cryptography is that a secret can be encrypted with multiple users and requires multiple users to decrypt. The quantum threshold cryptography is proposed by using idea of multiple bases. This can be considered as step forward towards multiparty quantum communication. This dissertation also proposed layered architecture for key distribution.
Concisely, this dissertation proposes the techniques like multicasting in quantum scenario, quantum threshold cryptography to achieve the goal of secured global communication
A Survey on Wireless Sensor Network Security
Wireless sensor networks (WSNs) have recently attracted a lot of interest in
the research community due their wide range of applications. Due to distributed
nature of these networks and their deployment in remote areas, these networks
are vulnerable to numerous security threats that can adversely affect their
proper functioning. This problem is more critical if the network is deployed
for some mission-critical applications such as in a tactical battlefield.
Random failure of nodes is also very likely in real-life deployment scenarios.
Due to resource constraints in the sensor nodes, traditional security
mechanisms with large overhead of computation and communication are infeasible
in WSNs. Security in sensor networks is, therefore, a particularly challenging
task. This paper discusses the current state of the art in security mechanisms
for WSNs. Various types of attacks are discussed and their countermeasures
presented. A brief discussion on the future direction of research in WSN
security is also included.Comment: 24 pages, 4 figures, 2 table
Recent Progress in the Quantum-to-the-Home Networks
For secure data transmission to the end users in a conventional fiber-to-the-home (FTTH) network, quantum cryptography (QC) is getting much consideration nowadays. QC or more specifically quantum key distribution (QKD) promises unconditionally secure protocol, the Holy Grail of communication and information security that is based on the fundamental laws of quantum physics. In this chapter, we discuss the design issues in a hybrid quantum-classical communication network, performance of the cost-effective off-the-shelf telecommunication equipment, our latest results on a four-state (Quadrature Phase Shift Keying, ‘QPSK’) RF sub-carrier assisted continuous-variable quantum key distribution (CV-QKD) multiuser network based on ultra-low loss quantum channel (pure silica core fiber, ‘PSCF’) and microelectromechanical systems (MEMS) based add/drop switch. The results are thoroughly compared with the commercially available high-cost encryption modules. It is expected that the discussed cost-effective and energy efficient QKD network can facilitate the practical applications of the CV-QKD protocol on the commercial scale in near future for smart access networks
Scalable and Adaptively Secure Any-Trust Distributed Key Generation and All-hands Checkpointing
The classical distributed key generation protocols (DKG) are resurging due to
their widespread applications in blockchain. While efforts have been made to
improve DKG communication, practical large scale deployments are still yet to
come, due to various challenges including broadcast channel scalability and
worst-case complaint phase. In this paper, we propose a practical DKG for
DL-based cryptosystems, with only (quasi-)linear computation/communication cost
per participant, with the help of a public ledger, and beacon; Notably, our DKG
only incurs constant-size blockchain storage cost for broadcast, even in the
face of worst-case complaints. Moreover, our protocol satisfies adaptive
security. The key to our improvements lies in delegating the most costly
operations to an Any-Trust group. This group is randomly sampled and consists
of a small number of individuals. The population only trusts that at least one
member in the group is honest, without knowing which one. Additionally, we
introduce an extended broadcast channel based on a blockchain and data
dispersal network (such as IPFS), enabling reliable broadcasting of
arbitrary-size messages at the cost of constant-size blockchain storage, which
may be of independent interest.
Our DKG leads to a fully practical instantiation of Filecoin's checkpointing
mechanism, in which all validators of a Proof-of-Stake (PoS) blockcahin
periodically run DKG and threshold signing to create checkpoints on Bitcoin,
thereby enhancing the security of the PoS chain. In comparison with another
checkpointing approach of Babylon (Oakland, 2023), ours enjoys a significally
smaller monetary cost of Bitcoin transaction fees. For a PoS chain with
validators, our cost is merely 0.6\% of that incurred by Babylon's
approach.Comment: 21 pages, 3 figure
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