947 research outputs found
A Byzantine Fault Tolerant Distributed Commit Protocol
In this paper, we present a Byzantine fault tolerant distributed commit
protocol for transactions running over untrusted networks. The traditional
two-phase commit protocol is enhanced by replicating the coordinator and by
running a Byzantine agreement algorithm among the coordinator replicas. Our
protocol can tolerate Byzantine faults at the coordinator replicas and a subset
of malicious faults at the participants. A decision certificate, which includes
a set of registration records and a set of votes from participants, is used to
facilitate the coordinator replicas to reach a Byzantine agreement on the
outcome of each transaction. The certificate also limits the ways a faulty
replica can use towards non-atomic termination of transactions, or semantically
incorrect transaction outcomes.Comment: To appear in the proceedings of the 3rd IEEE International Symposium
on Dependable, Autonomic and Secure Computing, 200
Radio Co-location Aware Channel Assignments for Interference Mitigation in Wireless Mesh Networks
Designing high performance channel assignment schemes to harness the
potential of multi-radio multi-channel deployments in wireless mesh networks
(WMNs) is an active research domain. A pragmatic channel assignment approach
strives to maximize network capacity by restraining the endemic interference
and mitigating its adverse impact on network performance. Interference
prevalent in WMNs is multi-faceted, radio co-location interference (RCI) being
a crucial aspect that is seldom addressed in research endeavors. In this
effort, we propose a set of intelligent channel assignment algorithms, which
focus primarily on alleviating the RCI. These graph theoretic schemes are
structurally inspired by the spatio-statistical characteristics of
interference. We present the theoretical design foundations for each of the
proposed algorithms, and demonstrate their potential to significantly enhance
network capacity in comparison to some well-known existing schemes. We also
demonstrate the adverse impact of radio co- location interference on the
network, and the efficacy of the proposed schemes in successfully mitigating
it. The experimental results to validate the proposed theoretical notions were
obtained by running an exhaustive set of ns-3 simulations in IEEE 802.11g/n
environments.Comment: Accepted @ ICACCI-201
Energy efficient mining on a quantum-enabled blockchain using light
We outline a quantum-enabled blockchain architecture based on a consortium of
quantum servers. The network is hybridised, utilising digital systems for
sharing and processing classical information combined with a fibre--optic
infrastructure and quantum devices for transmitting and processing quantum
information. We deliver an energy efficient interactive mining protocol enacted
between clients and servers which uses quantum information encoded in light and
removes the need for trust in network infrastructure. Instead, clients on the
network need only trust the transparent network code, and that their devices
adhere to the rules of quantum physics. To demonstrate the energy efficiency of
the mining protocol, we elaborate upon the results of two previous experiments
(one performed over 1km of optical fibre) as applied to this work. Finally, we
address some key vulnerabilities, explore open questions, and observe
forward--compatibility with the quantum internet and quantum computing
technologies.Comment: 25 pages, 5 figure
A Decentralized Dynamic PKI based on Blockchain
The central role of the certificate authority (CA) in traditional public key infrastructure (PKI) makes it fragile and prone to compromises and operational failures. Maintaining CAs and revocation lists is demanding especially in loosely-connected and large systems. Log-based PKIs have been proposed as a remedy but they do not solve the problem effectively. We provide a general model and a solution for decentralized and dynamic PKI based on a blockchain and web of trust model where the traditional CA and digital certificates are removed and instead, everything is registered on the blockchain. Registration, revocation, and update of public keys are based on a consensus mechanism between a certain number of entities that are already part of the system. Any node which is part of the system can be an auditor and initiate the revocation procedure once it finds out malicious activities. Revocation lists are no longer required as any node can efficiently verify the public keys through witnesses
INCORPORATING RADIO FREQUENCY MESH NETWORKS TO LINK LIVE, VIRTUAL, CONSTRUCTIVE TRAINING
Given the importance of modeling and simulation (M&S) for creating realistic training environments and employing or developing tactical systems for warfighters, the Department of Defense is turning toward live, virtual, constructive (LVC) simulations as a means to prepare and equip our military for the next war. M&S offers a unique competency for modeling emergent enemy behaviors in constructive simulations on virtual battlefields across the globe. Transferring these dynamic tactical actions to live command and control (C2) systems used during training can create decision-making opportunities for distributed units to react to and act upon. The research conducted in this thesis assessed, developed, and implemented an appropriate LVC environment that can be used in training for tactical convoy operations in the Marine Corps. We developed a robust mesh network connected to a personal computer running a constructive simulation to create dynamic tracks on handheld, Android-based C2 systems. Using low-bandwidth radios to create the network, we were able to create a rich, tactically realistic training environment while minimally increasing the combat load of our Marines. The system we created has the same functionality of the blue force tracker (BFT). Because the BFT is no longer funded, we recommend the LVC solution we created for this thesis as a potential replacement with embedded training capabilities.Captain, United States Marine CorpsApproved for public release. distribution is unlimite
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