930 research outputs found
Proof of User Similarity: the Spatial Measurer of Blockchain
Although proof of work (PoW) consensus dominates the current blockchain-based
systems mostly, it has always been criticized for the uneconomic brute-force
calculation. As alternatives, energy-conservation and energy-recycling
mechanisms heaved in sight. In this paper, we propose proof of user similarity
(PoUS), a distinct energy-recycling consensus mechanism, harnessing the
valuable computing power to calculate the similarities of users, and enact the
calculation results into the packing rule. However, the expensive calculation
required in PoUS challenges miners in participating, and may induce plagiarism
and lying risks. To resolve these issues, PoUS embraces the best-effort schema
by allowing miners to compute partially. Besides, a voting mechanism based on
the two-parties computation and Bayesian truth serum is proposed to guarantee
privacy-preserved voting and truthful reports. Noticeably, PoUS distinguishes
itself in recycling the computing power back to blockchain since it turns the
resource wastage to facilitate refined cohort analysis of users, serving as the
spatial measurer and enabling a searchable blockchain. We build a prototype of
PoUS and compare its performance with PoW. The results show that PoUS
outperforms PoW in achieving an average TPS improvement of 24.01% and an
average confirmation latency reduction of 43.64%. Besides, PoUS functions well
in mirroring the spatial information of users, with negligible computation time
and communication cost.Comment: 12 pages,10 figure
Delay Impact on Stubborn Mining Attack Severity in Imperfect Bitcoin Network
Stubborn mining attack greatly downgrades Bitcoin throughput and also
benefits malicious miners (attackers). This paper aims to quantify the impact
of block receiving delay on stubborn mining attack severity in imperfect
Bitcoin networks. We develop an analytic model and derive formulas of both
relative revenue and system throughput, which are applied to study attack
severity. Experiment results validate our analysis method and show that
imperfect networks favor attackers. The quantitative analysis offers useful
insight into stubborn mining attack and then helps the development of
countermeasures.Comment: arXiv admin note: text overlap with arXiv:2302.0021
Decentralizing Trust with Resilient Group Signatures in Blockchains
Blockchains have the goal of promoting the decentralization of transactions in a P2Pbased
internetworking model that does not depend on centralized trust parties. Along
with research on better scalability, performance, consistency control, and security guarantees
in their service planes, other challenges aimed at better trust decentralization and
fairness models on the research community’s agenda today.
Asymmetric cryptography and digital signatures are key components of blockchain
systems. As a common flaw in different blockchains, public keys and verification of
single-signed transactions are handled under the principle of trust centralization. In this
dissertation, we propose a better fairness and trust decentralization model by proposing
a service plane for blockchains that provides support for collective digital signatures
and allowing transactions to be collaboratively authenticated and verified with groupbased
witnessed guarantees. The proposed solution is achieved by using resilient group
signatures from randomly and dynamically assigned groups. In our approach we use
Threshold-Byzantine Fault Tolerant Digital Signatures to improve the resilience and robustness
of blockchain systems while preserving their decentralization nature.
We have designed and implemented a modular and portable cryptographic provider
that supports operations expressed by smart contracts. Our system is designed to be a
service plane agnostic and adaptable to the base service planes of different blockchains.
Therefore, we envision our solution as a portable, adaptable and reusable plugin service
plane for blockchains, as a way to provide authenticated group-signed transactions with
decentralized auditing, fairness, and long-term security guarantees and to leverage a
better decentralized trust model. We conducted our experimental evaluations in a cloudbased
testbench with at least sixteen blockchain nodes distributed across four different
data centers, using two different blockchains and observing the proposed benefits.As blockchains tem principal objetivo de promover a descentralização das transações
numa rede P2P, baseada num modelo não dependente de uma autoridade centralizada.
Em conjunto com maior escalabilidade, performance, controlos de consistência e garantias
de segurança nos planos de serviço, outros desafios como a melhoria do modelo de
descentralização e na equidade estão na agenda da comunidade científica.
Criptografia assimétrica e as assinaturas digitais são a componente chave dos sistemas
de blockchains. Porém, as blockchains, chaves públicas e verificações de transações
assinadas estão sobre o princípio de confiança centralizada. Nesta dissertação, vamos
propor uma solução que inclui melhores condições de equidade e descentralização de
confiança, modelado por um plano de serviços para a blockchain que fornece suporte para
assinaturas coletivas e permite que as transações sejam autenticadas colaborativamente
e verificadas com garantias das testemunhadas. Isto será conseguido usando assinaturas
resilientes para grupos formados de forma aleatória e dinamicamente. A nossa solução
para melhorar a resiliência das blockchains e preservar a sua natureza descentralizada,
irá ser baseada em assinaturas threshold à prova de falhas Bizantinas.
Com esta finalidade, iremos desenhar e implementar um provedor criptográfico modelar
e portável para suportar operações criptográficas que podem ser expressas por
smart-contracts. O nosso sistema será desenhado de uma forma agnóstica e adaptável
a diferentes planos de serviços. Assim, imaginamos a nossa solução como um plugin
portável e adaptável para as blockchains, que oferece suporte para auditoria descentralizada,
justiça, e garantias de longo termo para criar modelo melhor da descentralização
da base de confiança. Iremos efetuar as avaliações experimentais na cloud, correndo o
nosso plano de serviço com duas implementações de blockchain e pelo menos dezasseis
nós distribuídos em quatro data centres, observando os benefícios da solução proposta
A P2P Networking Simulation Framework For Blockchain Studies
Recently, blockchain becomes a disruptive technology of building distributed applications (DApps). Many researchers and institutions have devoted their resources to the development of more effective blockchain technologies and innovative applications. However, with the limitation of computing power and financial resources, it is hard for researchers to deploy and test their blockchain innovations in a large-scape physical network.
Hence, in this dissertation, we proposed a peer-to-peer (P2P) networking simulation framework, which allows to deploy and test (simulate) a large-scale blockchain system with thousands of nodes in one single computer. We systematically reviewed existing research and techniques of blockchain simulator and evaluated their advantages and disadvantages.
To achieve generality and flexibility, our simulation framework lays the foundation for simulating blockchain network with different scales and protocols. We verified our simulation framework by deploying the most famous three blockchain systems (Bitcoin, Ethereum and IOTA) in our simulation framework.
We demonstrated the effectiveness of our simulation framework with the following three case studies: (a) Improve the performance of blockchain by changing key parameters or deploying new directed acyclic graph (DAG) structure protocol; (b) Test and analyze the attack response of Tangle-based blockchain (IOTA) (c) Establish and deploy a new smart grid bidding system for demand side in our simulation framework.
This dissertation also points out a series of open issues for future research
BQBCC: Design of an Augmented Bioinspired Model for Improving QoS of Blockchain IoT Deployments via Context-based Consensus
Blockchain-deployments are highly secure, but lack in terms of scalability due to exponential increase in mining delay w.r.t. chain lengths. To overcome these issues, researchers have proposes used for low-complexity mining, sharing techniques, and other machine learning optimizations. But these models either depend on underlying blockchain, or showcase larger computational delays, which limits their scalability levels. Moreover, most of these models do not consider consensus optimizations, which further limits their deployment capabilities for large-scale networks. To overcome these issues, this text proposes design of an efficient bioinspired model for improving QoS of blockchain IoT (Internet of Things) deployments via context-based consensus. The proposed model initially collects temporal mining performance from existing miner nodes, and deploys a novel Proof-of-Temporal Trust (PoTT) based consensus for validating responses of these miners. The PoTT Model uses temporal mining delay, energy consumed while mining, and throughput levels for selection of high-performance miners for processing block-addition requests. Requests approved by these miners are stored on a set of Bacterial Foraging Optimized (BFO) sidechains. These sidechains are automatically tuned based on spatial QoS performance of the network under real-time conditions. The BFO Model assists in segregating existing single-length blockchains into QoS-optimized sidechains. To perform this segregation, the BFO Model uses an exhaustive consistency metric that combines QoS & security levels that can be applied to specialized applications like Industrial IoTs. Thus, segregation into sidechains is done while maintaining high security under heterogenous attacks. Due to these optimizations, the model was able to reduce mining delay by 3.9%, reduce energy needed for mining by 2.5%, improve throughput by 4.5%, while maintaining high attack-detection efficiency under Sybil, Distributed Denial of Service (DDoS), and Masquerading attacks
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