Subject: Re: [bitcoin-dev] The Excessive-Block Gate: How a Bitcoin Unlimited Node Deals With Large Blocks

From: Sergio Demian Lerner <[email-masked]>
Date: Thu, 24 Nov 2016 22:39:05 -0300

Hi Peter,

How would a person or exchange decide to accept a payment in BU if it does
not know the gate policy of 51% of the miners?

Suppose that the exchange receives B1,S2,S3,S4 (a big block at height 1,
and 3 small blocks at height 2, 3 and 4), and an alternate chain A1,A2,A3
(three small blocks). The first is the longest, but the second may be the
one 51% of the miners will extend.

Without knowing  the policy of at least 51% of the miners (the maximum
acceptance depth) it's unclear if the exchange has to obey the longest
chain or the chain with higher probability of being extended.
If the maximum acceptance depth of the majority of miners is higher than 6
blocks, accepting a transaction with 6 confirmations is risky.
So BU would set a lower bound on the number of confirmations equal to the
maximum acceptance depth of the majority of miners.But miners do not
publish their acceptance depth, so basically users are clue-less. I think
miners should at least advertise their gate block size and acceptance depth
in their coinbase field.

Is there a game-theoretic analysis of confirmation blocks and their
probabilities in BU ?
Without a detailed analysis, unlimited block size seems a risky change to
Bitcoin, to me.

Regards, Sergio.

On Tue, Nov 22, 2016 at 1:31 PM, Peter R via bitcoin-dev <
[email-masked]> wrote:

> Dear all,
>
> Bitcoin Unlimited’s market-based solution to the block-size limit is
> slowly winning support from node operators and miners.  With this increased
> attention, many people are asking for a better explanation of how Bitcoin
> Unlimited actually works.  The article linked below describes how Bitcoin
> Unlimited’s excessive-block logic works from the perspective of a single
> node. (I’m hoping to do a follow-up article that describe how this
> “node-scale” behavior facilitates the emergence of a fluid and organic
> block size limit at the network scale.)
>
> https://medium.com/@peter_r/the-excessive-block-gate-how-
> a-bitcoin-unlimited-node-deals-with-large-blocks-22a4a5c322d4
>
> Best regards,
> Peter R
>
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