Re: [Bitcoin-development] Cut-through propagation of blocks

[Jonathan Levin <jonathan.levin@sant.ox.ac.uk>]

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I have done some work on incentives arising from block propagation times and it turns out that Bitcoin is already quite good at establishing the primacy of blocks by time despite what people think. Part of the reason for this is the way that partitions on the network evolve as a block is propagated. Typically at the moment, blocks reach over 50% of the network in 5 seconds. Reach being defined as a node receiving and validating a block. If we make an assumption that the hashing power of the network is uniformly distributed over the nodes (I know it is not a good assumption but can discuss it off the list). Then 50% of the hashing power are already building a block that builds on top of the block that is already circulating. The probability that there is a collision on the network therefore falls fast and then the probability that the miner who propagated the first block wins given a collision occurs is rising. I think that block propagation times might actually be a bigger issue for miners who are less well connected to the network in the sense that they spend more time mining redundant problems and during that time may find blocks to compete with blocks that are already spreading throughout the network.

I have a paper that models this more formally and has some numerical simulations but cannot publish it on the internet at present (University Regulations) but I am happy to share a version privately if anyone is interested.

Best,

Jonathan

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Jonathan Levin
Co-Founder Coinometrics
http://www.coinometrics.com/
Postgraduate Economist | St Antony's College | Oxford University
@jony_levin
@Coinometrics





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