PoSAT: Proof-of-Work Availability andUnpredictability, without the Work

10/15/2020
by   Soubhik Deb, et al.
0

An important feature of Proof-of-Work (PoW) blockchains is full dynamic availability, allowing miners to go online and offline while requiring only 50 of the online miners to be honest. Existing Proof-of-stake (PoS), Proof-of-Space and related protocols are able to achieve this property only partially, either putting the additional assumption that adversary nodes to be online from the beginning and no new adversary nodes come online afterwards, or use additional trust assumptions for newly joining nodes.We propose a new PoS protocol PoSAT which can provably achieve dynamic availability fully without any additional assumptions. The protocol is based on the longest chain and uses a Verifiable Delay Function for the block proposal lottery to provide an arrow of time. The security analysis of the protocol draws on the recently proposed technique of Nakamoto blocks as well as the theory of branching random walks. An additional feature of PoSAT is the complete unpredictability of who will get to propose a block next, even by the winner itself. This unpredictability is at the same level of PoW protocols, and is stronger than that of existing PoS protocols using Verifiable Random Functions.

READ FULL TEXT

Authors

page 1

page 2

page 3

page 4

05/21/2020

Everything is a Race and Nakamoto Always Wins

Nakamoto invented the longest chain protocol, and claimed its security b...
05/19/2020

Free2Shard: Adaptive-adversary-resistant sharding via Dynamic Self Allocation

Propelled by the growth of large-scale blockchain deployments, much rece...
01/06/2021

Highway: Efficient Consensus with Flexible Finality

There has been recently a lot of progress in designing efficient partial...
11/22/2020

TaiJi: Longest Chain Availability with BFT Fast Confirmation

Most state machine replication protocols are either based on the 40-year...
11/24/2021

Securing Proof-of-Stake Nakamoto Consensus Under Bandwidth Constraint

Satoshi Nakamoto's Proof-of-Work (PoW) longest chain (LC) protocol was a...
03/31/2022

Parallel Proof-of-Work with Concrete Bounds

Authorization is challenging in distributed systems that cannot rely on ...
09/10/2020

Ebb-and-Flow Protocols: A Resolution of the Availability-Finality Dilemma

The CAP theorem says that no blockchain can be live under dynamic partic...
This week in AI

Get the week's most popular data science and artificial intelligence research sent straight to your inbox every Saturday.