Message-ID: <535C5BBF.30709@monetize.io>
Date: Sat, 26 Apr 2014 18:22:07 -0700
From: Mark Friedenbach <mark@monetize.io>
Organization: Monetize.io Inc.
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Subject: Re: [Bitcoin-development] Proof-of-Stake branch?
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That makes double-spends trivially easy: sign two blocks, withholding
one. Then at a later point in time reveal the second signed block
(demonstrating your own fraud) and force a reorg.

On 04/26/2014 04:44 PM, Gareth Williams wrote:
> What about using fraud proofs? Your coinbase only matures if nobody publishes proof that you signed a competing block. 
> 
> Then something is at least at stake. When it's your chance to sign a block, attempting to sign and publish more than one at the same height reliably punishes you (you effectively waste your chance and receive no reward.)
> 
> I can't remember who I saw discussing this idea. Might have been Vitalik Buterin?
> 
> On 27 April 2014 6:39:28 AM AEST, Mark Friedenbach <mark@monetize.io> wrote:
>> There's no need to be confrontational. I don't think anyone here
>> objects
>> to the basic concept of proof-of-stake. Some people, myself included,
>> have proposed protocols which involve some sort of proof of stake
>> mechanism, and the idea itself originated as a mechanism for
>> eliminating
>> checkpoints, something which is very much on topic and of concern to
>> many here.
>>
>> The problems come when one tries to *replace* proof-of-work mining with
>> proof-of-stake "mining." You encounter problems related to the fact
>> that
>> with proof-of-stake nothing is actually at stake. You are free to sign
>> as many different forks as you wish, and worse have incentive to do so,
>> because whatever fork does win, you want it to be yours. In the worst
>> case this results in double-spends at will, and in the best case with
>> any of the various proposed protections deployed, it merely reduces to
>> proof-of-work as miners grind blocks until they find one that names
>> them
>> or one of their sock puppets as the signer of the next block.
>>
>> I sincerely doubt you will find a solution to this, as it appears to be
>> a fundamental issue with proof-of-stake, in that it must leverage an
>> existing mechanism for enforced scarcity (e.g. proof-of-work) in order
>> to work in a consensus algorithm. Is there some solution that you have
>> in mind for this?
>>
>> Mark
>>
>> On 04/25/2014 12:33 AM, Troy Benjegerdes wrote:
>>> Do it. Someone will scream harm. The loudest voices screaming how it
>> would
>>> be harmful are doing the most harm.
>>>
>>> The only way to know is build it, and test it. If the network breaks,
>> then
>>> it is better we find out sooner rather than later.
>>>
>>> My only suggestion is call it 'bitstake' or something to clearly
>> differentiate
>>> it from Bitcoin. This also might be an interesting application of the
>> side
>>> chains concept Peter Todd has discussed.
>>>
>>> On Thu, Apr 24, 2014 at 04:32:15PM -0700, Stephen Reed wrote:
>>>> Hello all.
>>>>
>>>> I understand that Proof-of-Stake as a replacement for Proof-of-Work
>> is a prohibited yet disputed change to Bitcoin Core. I would like to
>> create a Bitcoin branch that provides a sandboxed testbed for
>> researching the best PoS implementations. In the years to come, perhaps
>> circumstances might arise, such as shifting of user opinion as to
>> whether PoS should be moved from the prohibited list to the hard-fork
>> list.
>>>> -----
>>>>
>>>> A poll I conducted today on bitcointalk,
>> https://bitcointalk.org/index.php?topic=581635.0 with an
>> attention-grabbing title suggests some minority support for Bitcoin
>> Proof-of-Stake. I invite any of you to critically comment on that
>> thread.
>>>>
>>>> "Annual 10% bitcoin dividends can be ours if  Proof-of-Stake full
>> nodes outnumber existing Proof-of-Work full nodes by three-to-one. What
>> is your choice?"
>>>>
>>>> "I do not care or do not know enough." - 5 (16.1%) 
>>>> "I would download and run the existing Proof-of-Work program to
>> fight the change." - 14 (45.2%) 
>>>> "I would download and run the new Proof-of-Stake program to favor
>> the change. " - 12 (38.7%) 
>>>> Total Voters: 31 
>>>> -----
>>>>
>>>> Before I branch the source code and learn the proper way of doing
>> things in this community, I ask you simply if creating the branch is
>> harmful? My goal is to develop, test and document PoS, while exploring
>> its vulnerabilities and fixing them in a transparent fashion.
>>>>
>>>> Thanks for taking a bit of your time to read this message.
>>>
>>>
>>>
>>>
>>
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