237 research outputs found
On the Security and Performance of Proof of Work Blockchains
Proof of Work (PoW) powered blockchains currently account for more than 90% of the total market capitalization of existing digital currencies. Although the security provisions of Bitcoin have been thoroughly analysed, the security guarantees of variant (forked) PoW blockchains (which were instantiated with different parameters) have not received much attention in the literature.
In this paper, we introduce a novel quantitative framework to analyse the security and performance implications of various consensus and network parameters of PoW blockchains. Based on our framework, we devise optimal adversarial strategies for double-spending and selfish mining while taking into account real world constraints such as network propagation, different block sizes, block generation intervals, information propagation mechanism, and the impact of eclipse attacks. Our framework therefore allows us to capture existing PoW-based deployments as well as PoW blockchain variants that are instantiated with different parameters, and to objectively compare the tradeoffs between their performance and security provisions
Selecting Miners within Blockchain-based Systems Using Evolutionary Algorithms for Energy Optimisation
In this paper, we represent the problem of selecting miners within a
blockchain-based system as a subset selection problem. We formulate the problem
of minimising blockchain energy consumption as an optimisation problem with two
conflicting objectives: energy consumption and trust. The proposed model is
compared across different algorithms to demonstrate its performance.Comment: To appear in 2021 Genetic and Evolutionary Computation Conference
Companion (GECCO '21 Companion), July 10--14, 2021, Lille, Franc
Secure and Trustable Electronic Medical Records Sharing using Blockchain
Electronic medical records (EMRs) are critical, highly sensitive private
information in healthcare, and need to be frequently shared among peers.
Blockchain provides a shared, immutable and transparent history of all the
transactions to build applications with trust, accountability and transparency.
This provides a unique opportunity to develop a secure and trustable EMR data
management and sharing system using blockchain. In this paper, we present our
perspectives on blockchain based healthcare data management, in particular, for
EMR data sharing between healthcare providers and for research studies. We
propose a framework on managing and sharing EMR data for cancer patient care.
In collaboration with Stony Brook University Hospital, we implemented our
framework in a prototype that ensures privacy, security, availability, and
fine-grained access control over EMR data. The proposed work can significantly
reduce the turnaround time for EMR sharing, improve decision making for medical
care, and reduce the overall costComment: AMIA 2017 Annual Symposium Proceeding
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