Subject: Re: [bitcoin-dev] Hash of UTXO set as consensus-critical

From: Justus Ranvier <[email-masked]>
Date: Fri, 18 Sep 2015 21:30:13 -0500

On 18/09/15 15:17, Rune Kjær Svendsen via bitcoin-dev wrote:
> Bitcoin does not function if the majority of mining power is dishonest. There is no way around that. It’s how proof-of-work functions.

None of those statements are true.

If a majority of Bitcoin miners are mining invalid blocks, then they
aren't Bitcoin miners any more and are no longer relevant to the Bitcoin
consensus.

There does exist a problem that light clients aren't always able to tell
the difference between chains that are valid and chains that are not
valid, but it's is possible to create simple proofs that would do so:

https://gist.github.com/justusranvier/451616fa4697b5f25f60

If those changes would be implemented, then any node that knew a chain
was invalid could produce a compact proof that anyone else in the
network could verify, regardless of how much proof of work was used to
create the invalid chain.

Committed UTXO sets would need safe to rely upon if a similar set of
proofs that a particular set was invalid existed.

-- 
Justus Ranvier
Open Bitcoin Privacy Project
http://www.openbitcoinprivacyproject.org/
[email-masked]
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