This Week in Blockchain Research Issue #17
|zk Capital||Jul 17, 2019|
Paper of the Week:
Tolerating Byzantine node failures and asynchronous network conditions makes consensus protocols complex and fragile, while relying on synchrony assumptions and timeouts can make consensus protocols vulnerable to performance and routing-based attacks.
This work presents a new approach to asynchronous consensus that decomposes the handling of time from the consensus process itself. The protocol is simple, provides clean layering, and requires no common coins or trusted dealers.
Inspired in part by Lamport clocks, vector clocks, and matrix clocks, a new Threshold Logical Clock (TLC) protocol is introduced that synthesizes a virtual notion of time on an asynchronous network and operates in the presence of failed or Byzantine nodes, allowing other protocols such as threshold signing, randomness beacons, and consensus to be built more simply atop it, as if on a synchronous network.
To explore TLC’s capabilities, a “propose, gossip, decide” approach is developed such that participants each (i) propose a potential value to agree on then simply wait a number of TLC time steps, (ii) record and gossip their observations at each step, and finally (ii) decide independently on the basis of public randomness and the history they observed whether the consensus round succeeded and, if so, which value was agreed on.
To handle network asynchrony, including adversarial scheduling, it is sufficient to associate random tickets with each proposed value or block for symmetry-breaking, while ensuring that the network adversary cannot learn the random ticket values until the communication pattern defining the consensus round has been completed and indelibly fixed.
To tolerate f-Byzantine nodes colluding with the network adversary, this work relies on gossip and digital signatures, treating all participants as accountable state machines to handle equivocation and other detectable misbehavior by faulty nodes.
Furthermore, threshold public randomness via secret sharing is used to ensure that the adversary can neither learn nor bias proposal ticket values until the round has completed.
Authors: Bryan Ford*,
Affiliations: * EPFL.
1. Paper Title: On Analysis of the Bitcoin and Prism Backbone Protocols.
Summary: This work proves a blockchain growth property and a blockchain quality property of the leader sequence in the Prism protocol showing that the leader sequence is permanent with high probability after sufficient amount of wait time.
Affiliations: * Northwestern University.
1. Paper Title: TICK: Tiny Client for Blockchains.
Summary: The first blockchain system that gives the ability of transaction verification to light client that only needs to download a constant and small size of data.
Authors: Wei Zhang*, Jiangshan Yu†, and Qingqiang He* and Nan Guan*,
Summary: A new blockchain protocol which aims at improving scalability of the block-wise Byzantine agreement approach by combining sharding techniques, users presence and stake transfer to operate in a PoS setting.
Summary: This work develops a model in Coq of the Algorand consensus protocol and outlines the specification and formal proof of its asynchronous safety opening up many possibilities for further formal verification of the protocol, most directly of liveness properties.
Summary: This paper documents a sharp increase in corporate Blockchain disclosures through 8-K filings during a Blockchain mania.
Affiliations: * Tulane University.
2. Paper Title: Blockchain Development and Fiduciary Duty.
Summary: This work argues that public blockchain protocol developers do not function as corporate fiduciaries, and further that labeling protocol developers as fiduciaries would be impractical and have other negative effects including potentially destroying the open source production model.
Summary: Bitcoin, Ethereum, and Libra have jumpstarted the movement of decentralized finance, which leverages blockchain technology to create a new financial system that is decentralized, open, permissionless, and borderless.
Authors: Yan Chen*,
Affiliations: * Stevens Institute of Technology.
Summary: This study sheds light on the potential application of blockchain technology in financial accounting and its possible impacts.
“Significant research in the blockchain space is constantly being achieved by academic researchers. Unfortunately, a lot of this research is overlooked due to the massive numbers of papers being generated and the way they are being promoted and published. We’ve put together a categorized list of academic papers that can guide our subscribers and keep them up to date.”
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