[Bitcoin-development] questions about bitcoin-XT code fork & non-consensus hard-fork

[Pindar Wong]

On Tue, Jun 16, 2015 at 2:03 AM, Adam Back <adam at cypherspace.org> wrote:

> Hi Mike
>
> Well thank you for replying openly on this topic, its helpful.
>
> I apologise in advance if this gets quite to the point and at times
> blunt, but transparency is important, and we owe it to the users who
> see Bitcoin as the start of a new future and the$3b of invested funds
> and $600m of VC funds invested in companies, we owe it to them that we
> be open and transparent here.
>
> I would really prefer on a personal nor professional basis to be
> having this conversation period, never mind in public, but Mike - your
> and Gavin's decision to promote a unilateral hard-fork and code fork
> are extremely high risk for bitcoin and so there remains little
> choice.  So I apologise again that we have to have this kind of
> conversation on a technical discussion list.  This whole thing is
> hugely stressful and worrying for developers, companies and investors.
>
> I strongly urge that we return to the existing collaborative
> constructive review process that has been used for the last 4 years
> which is a consensus by design to prevent one rogue person from
> inserting a backdoor, or lobbying for a favoured change on behalf of a
> special interest group, or working for bad actor (without accusing you
> of any of those - I understand you personally just want to scale
> bitcoin, but are inclined to knock heads and try to force an issue you
> see, rather than work collaboratively).
>
> For you (and everyone)
>
> - Should there be a summit of some kind, that is open attendance, and
> video recorded so that people who are unable to attend can participate
> too, so that people can present the technical proposals and risks in
> an unbiased way?
>
>
Dear Adam, All:

At the community's convenience, it would be an honour to arrange an initial
open summit to meet with representatives of the Chinese miners in Hong Kong
(UTC+8) to facilitate a better understand between the different
stakeholders of the Bitcoin ecosystem on this important issue.   This could
be arranged for this October, or earlier, if deemed necessary.

Remote online participation would be welcome from those who might not be
able to attend in person.

However,  it is hoped that such a meeting would be primarily document
driven to facilitate orderly translation, discussion and decision.

p.



> (It is not theoretical question, I may have a sponsor and host - not
> Blockstream, an independent, its a question for everyone, developers,
> users, CTOs, CEOs.)
>
>
>
> So here I come back to more frank questions:
>
> Governance
>
> The rest of the developers are wise to realise that they do not want
> exclusive control, to avoid governance centralising into the hands of
> one person, and this is why they have shared it with a consensus
> process over the last 4 years.  No offence but I dont think you
> personally are thinking far enough ahead to think you want personal
> control of this industry.  Maybe some factions dont trust your
> motives, or they dont mind, but feel more assured if a dozen other
> people are closely reviewing and have collective review authority.
>
> - Do you understand that attempting to break this process by
> unilateral hard-fork is extremely weakening of Bitcoin's change
> governance model?
>
> - Do you understand that change governance is important, and that it
> is important that there be multiple reviewers and sign-off to avoid
> someone being blackmailed or influenced by an external party - which
> could potentially result in massive theft of funds if something were
> missed?
>
> - Secondarily do you understand that even if you succeed in a
> unilateral fork (and the level of lost coins and market cap and damage
> to confidence is recoverable), that it sets a precedent that others
> may try to follow in the future to introduce coercive features that
> break the assurances of bitcoin, like fungibility reducing features
> say (topically I hear you once proposed on a private forum the concept
> of red-lists, other such proposals have been made and quickly
> abandoned), or ultimately if there is a political process to obtain
> unpopular changes by unilateral threat, the sky is the limit - rewrite
> the social contract at that point without consensus, but by
> calculation that people will value Bitcoin enough that they will
> follow a lead to avoid risk to the system?
>
>
> Security
>
> As you probably know some extremely subtle bugs in Bitcoin have at
> times slipped past even the most rigorous testings, often with
> innocuous but unexpected behaviours, but some security issues  Some
> extremely intricate and time-sensitive security defect and incident
> response happens from time to time which is not necessarily publicly
> disclosed until after the issue has been rolled out and fixed, which
> can take some time due to the nature of protocol upgrades,
> work-arounds, software upgrade via contacting key miners etc.  We
> could take an example of the openSSL bug.
>
> - How do you plan to deal with security & incident response for the
> duration you describe where you will have control while you are
> deploying the unilateral hard-fork and being in sole maintainership
> control?
>
> - Are you a member of the bitcoin security reporting list?
>
> On 15 June 2015 at 11:56, Mike Hearn <mike at plan99.net> wrote:
> > I will review both and mostly delegate to Gavin's good taste around the
> > details, unless there is some very strong disagreement. But that seems
> > unlikely.
> > ...
> > Feedback will be read. There are no NACKS in Bitcoin XT. Patch requests
> > aren't scored in any way. The final decision rests with the maintainer
> as in
> > ~all open source projects.
>
> As you know the people who have written 95% of the code (and reviewed,
> and tested, and formally proved segments etc) are strenuously advising
> not to push any consensus code into public use without listening to
> and addressing review questions which span beyond rigorous code &
> automated guided fuzz testers, simulation and sometimes formal proofs,
> but also economics, game-theory and critically very subtle
> determinism/consensus safety that they have collectively 4-5 years
> experience of each.
>
> - Will you pause your release plans if all of the other developers
> insist that the code or algorithm is defective?
>
> - Please don't take this the wrong way, and I know your bitcoinj work
> was a significant engineering project which required porting bitcoin
> logic.  But If the answer to the above question is no, as you seemed
> to indicate in your response, as you not have not written much bitcoin
> core code yourself (I think 3 PRs in total), do you find yourself more
> qualified than the combination of peer review of the group of people
> who have written 95% of it, and maintained it and refactored most of
> it over the last 4-5 years?
>
> I presume from your security background you are quite familiar with
> the need for review of crypto protocol changes & rigorous code review.
> That is even more the case with Bitcoin given the consensus
> criticality.
>
> >> - On the idea of a non-consensus hard-fork at all, I think we can
> >> assume you will get a row of NACKs.  Can you explain your rationale
> >> for going ahead anyway?  The risks are well understood and enormous.
> >
> > If Bitcoin runs out of capacity it will break and many of our users will
> > leave. That is not an acceptable outcome for myself or the many other
> > wallet, service and merchant developers who have worked for years to
> build
> > an ecosystem around this protocol.
>
> That you are frustrated, is not a sufficient answer as to why you are
> proposing to go ahead with a universally acknowledged extreme network
> divergence danger unilateral hard-fork, lacking wide-spread consensus.
> People are quite concerned about this.  Patience, caution and prudence
> is necessary in a software system with such high assurance
> requirements.
>
> So I ask again:
>
> - On the idea of a non-consensus hard-fork at all, I think we can
> assume you will get a row of NACKs.  Can you explain your rationale
> for going ahead anyway?  The risks are well understood and enormous.
>
> Note the key point is that you are working on a unilateral hard-fork,
> where there is a clear 4 year established process for proposing
> improvements and an extremely well thought out and important change
> management governance process.  While there has been much discussion,
> you nor Gavin, have not actually posted a BIP for review.  Nor
> actually was much of the discussion even conducted in the open: it was
> only when Matt felt the need to clear the air and steer this
> conversation into the open that discussion arose here.  During that
> period of private discussion you and Gavin were largely unknown to
> most of us lobbying companies with your representation of a method
> that concerns everyone of the Bitcoin users.  Now that the technical
> community aware aware they are strenuously discouraging you on the
> basis of risks.
>
>
> Openness
>
> - Do you agree that bitcoin technical discussions should happen in the
> open?
>
> - As this is a FOSS project, do you agree that companies should also
> be open, about their requirements and trade-offs they would prefer?
>
> - Can you disclose the list of companies you have lobbied in private
> whether they have spoken publicly or not, and whether they have
> indicated approval or not?
>
> - Did you share a specific plan, like a BIP or white paper with these
> companies, and if so can we see it?
>
> - If you didnt submit a plan, could you summarise what you asked them
> and what you proposed, and if you discussed also the risks?  (If you
> asked them if they would like Bitcoin to scale, I expect almost
> everyone does, including every member of the technical community, so
> that for example would not fairly indicate approval for a unilateral
> hard-fork)
>
> I and others will be happy to talk with the CTO and CEOs of companies
> you have lobbied in private, for balance to assure ourselves and the
> rest of the community that their support was given - and with full
> understanding of the risks of doing it unilaterally, without peer
> review, benefit of maintenance and security inidence management, and
> what exactly they are being quoting as having signed up for.
>
> (This maybe more efficiently and openly achieved by the open process,
> on a mailing list, maybe a different one even special purpose to this
> topic, with additional option of the open public meeting I proposed at
> the top).
>
> - Do you agree that it would be appropriate, that companies be aware
> of both the scaling opportunities (of course, great everyone wants
> scalability) as well as the technical limits and risks with various
> approaches?  And that these be presented by parties from a range of
> views to ensure balance?
>
> - Do you consider your expression of issues to hold true to the ideal
> of representing balanced nuanced view of all sides of a technical
> debate, even when under pressure or feeling impatient about the
> process?
>
> You may want to review the opening few minutes of your epicenter 82
> bitcoin for example where you claimed and I quote "[the rest of the
> technical community] dont want capacity to ever increase and want it
> to stay where it is and when it fills up people move to other
> systems".
>
> - Do you think that is an accurate depiction of the complex trade-offs
> we have been discussing on this list?
>
> (For the record I am not aware of a single person who has said they do
> not agree with scaling Bitcoin.  Changing a constant is not the
> hard-part.  The hard part is validating a plan and the other factors
> that go into it.  It's not a free choice it is a security/scalability
> tradeoff.  No one will thank us if we "scale" bitcoin but break it in
> hard to recover ways at the same time.)
>
> - Were you similarly balanced in your explanations when talking to
> companies in private discussions?
>
> - Do you understand that if we do not work from balanced technical
> discussion, that we may end up with some biased criteria?
>
> Authority
>
> Neither you nor Gavin have any particular authority here to speak on
> behalf of Bitcoin (eg you acknowledge in your podcast that Wladimir is
> dev lead, and you and Gavin are both well aware of the 4 year
> established change management consensus decision making model where
> all of the technical reviewers have to come to agreement before
> changes go in for security reasons explained above).  I know Gavin has
> a "Chief Scientist" title from the Bitcoin Foundation, but sadly that
> organisation is not held in as much regard as it once was, due to
> various irregularities and controversies, and as I understand it no
> longer employs any developers, due to lack of funds.  Gavin is now
> employed by MIT's DCI project as a researcher in some capacity.  As
> you know Wladimir is doing the development lead role now, and it seems
> part of your personal frustration you said was because he did not
> agree with your views.  Neither you nor Gavin have been particularly
> involved in bitcoin lately, even Gavin, for 1.5 years or so.
>
> - Do you agree that if you presume to speak where you do not have
> authority you may confuse companies?
>
> > If Bitcoin runs out of capacity it will break and many of our users will
> > leave. That is not an acceptable outcome for myself or the many other
> > wallet, service and merchant developers who have worked for years to
> build
> > an ecosystem around this protocol.
>
> But I think this is a false dichotomy.  As I said in previous mail I
> understand people are frustrated that it has taken so long, but it is
> not the case that no progress has been made on scalability.
>
> I itemised a long list of scalability work which you acknowledged as
> impressive work (CPU, memory, network bandwidth/latency) and RBF, CPFP
> fee work, fee-estimation, and so on, which you acknowledged and are
> aware of.
>
> There are multiple proposals and BIPs under consideration on the list
> right now.
>
> - what is the reason that you (or Gavin) would not post your BIP along
> side the others to see if it would win based on technical merit?
>
> - why would you feel uniquely qualified to override the expert opinion
> of the rest of the technical community if your proposal were not
> considered to have most technical merit? (Given that this is not a
> simple market competition thing where multiple hard-forks can be
> considered - it is a one only decision, and if it is done in a
> divisive unilateral way there are extreme risks of the ledger
> diverging.)
>
> Network Divergence Risk
>
> >> - How do you propose to deal with the extra risks that come from
> >> non-consensus hard-forks?  Hard-forks themselves are quite risky, but
> >> non-consensus ones are extremely dangerous for consensus.
> >
> > The approach is the same for other forks. Voting via block versions and
> then
> > when there's been >X% for Y time units the 1mb limit is lifted/replaced.
>
> But this is not a soft-fork, it is a hard-fork.  Miner voting is only
> peripherally related.  Even if in the extremis 75% of miners tried a
> unilateral hard-fork but 100% of the users stayed on the maintained
> original code, no change would occur other than those miners losing
> reward (mining fork-coins with no resale value) and the difficulty
> would adjust.  The miners who made an error in choice would lose money
> and go out of business or rejoin the chain.
>
> However if something in that direction happens with actual users and
> companies on both sides of it users will lose money, the ledger will
> diverge as soon as a single double-spend happens, and never share a
> block again, companies will go instantly insolvent, and chaos will
> break out.  This is the dangerous scenario we are concerned about.
>
> So the same question again:
>
> - How do you propose to deal with the extra risks that come from
> non-consensus hard-forks?  Hard-forks themselves are quite risky, but
> non-consensus ones are extremely dangerous for consensus.
>
>
> Being sensitive to alarming the market
>
> It is something akin to Greece or Portugal or Italy exiting the euro
> currency in a disorderly way.  Economists and central bank policy
> makers are extremely worried about such an eventuality and talk about
> related factors in careful, measured terms, watch Mario Draghi when he
> speaks.
>
> Imagine that bitcoin is 10x or 100x bigger.  Bitcoin cant have people
> taking unilateral actions such as you have been proposing.  It is not
> following the consensus governance process, and not good policy and it
> is probably affecting bitcoin confidence and price at this moment.
>
> >> - Do you have contingency plans for what to do if the non-consensus
> >> hard-fork goes wrong and $3B is lost as a result?
> >
> > Where did you get the $3B figure from? The fork either doesn't happen,
> or it
> > happens after quite a long period of people knowing it's going to happen
> -
> > for example because their full node is printing "You need to upgrade"
> > messages due to seeing the larger block version, or because they read the
> > news, or because they heard about it via some other mechanisms.
>
> This is not a soft-fork, and the community will not want to take the
> risks once they understand them, and they have months in which to
> understand them and at this point you've motivated and wasted 100s of
> developer man hours such that we will feel impelled to make sure that
> no one opts into a unilateral hard-fork without understanding the
> risks.  It would be negligent to allow people to do that.  Before this
> gets very far FAQs will be on bitcoin.org etc explaining this risk I
> would imagine.  Its just starting not finished.
>
> What makes you think the rest of the community may not instead prefer
> Jeff Garzik's BIP after revisions that he is making now with review
> comments from others?
>
> Or another proposal.  Taken together with a deployment plan that sees
> work on decentralisation tying into that plan.
>
> - If you persisted anyway, what makes you think bitcoin could not make
> code changes defensively relating to your unilateral fork?
> (I am sure creative minds can find some ways to harden bitcoin against
> a unilateral fork, with a soft-fork or non-consensus update can be
> deployed much faster than a hard-fork).
>
> I tried to warn Gavin privately that I thought he was under-estimating
> the risk of failure to his fork proposal due to it being unilateral.
> Ie as you both seem sincere in your wish to have your proposal
> succeed, then obviously the best way to do that is to release a BIP in
> the open collaborative process and submit it to review like everyone
> else.  Doing it unilaterally only increases its chance of failure.
>
> The only sensible thing to do here is submit a BIP and stop the
> unilateral fork threat.
>
> Scalability Plans
>
> > Let me flip the question around. Do you have a contingency plan if
> Bitcoin
> > runs out of capacity and significant user disruption occurs that results
> in
> > exodus, followed by fall in BTC price? The only one I've seen is "we can
> > perform an emergency hard fork in a few weeks"!
>
> Yes people have proposed other plans.  Bryan Bishop posted a list of them.
>
> Jeff Garzik has a proposal, BIP-100 which seems already better than
> Gavin's having benefit of peer review which he has been incorporating.
>
> I proposed several soft-fork models which can be deployed safely and
> immediately, which do not have ledger risk.
>
> I have another proposal relating to simplified soft-fork one-way pegs
> which I'll write up in a bit.
>
> I think there are still issues in Jeff's proposal but he is very open
> and collaborating and there maybe related but different proposals
> presently.
>
> >> As you can probably tell I think a unilateral fork without wide-scale
> >> consensus from the technical and business communities is a deeply
> >> inadvisable.
> >
> > Gavin and I have been polling many key players in the ecosystem. The
> > consensus you seek does exist. All wallet developers (except Lawrence),
> all
> > the major exchanges, all the major payment processors and many of the
> major
> > mining pools want to see the limit lifted (I haven't been talking to
> pools,
> > Gavin has).
>
> It does not seem to me that you understand the issue.  Of course they
> want to increase the scalability of bitcoin.  So does everyone else on
> this mailing list.
>
> That they would support that is obvious.  If you presented your
> unilateral action plan without explaining the risks too.
>
> I think I covered this further above.  If you would like to share the
> company list, or we can invite them to the proposed public physical
> meeting, I think it would be useful for them to have a balanced view
> of the ledger divergence risks, and alternative in-consensus proposals
> underway, as well as the governance risks, maintenance risks, security
> incident risks.
>
> Note that other people talk to companies too, as part of their day to
> day jobs, or from contacts from being in the industry.  You have no
> special authority or unique ability to talk with business people.  Its
> just that the technical community did not know you were busy doing
> that.
>
> I can not believe that any company that would listen to their CTO, CSO
> or failing that board would be ok with the risks implied by what you
> are proposing on full examination.
>
> > This notion that the change has no consensus is based on you polling the
> > people directly around you and people who like to spend all day on this
> > mailing list. It's not an accurate reflection of the wider Bitcoin
> community
> > and that is one of the leading reasons there is going to be a fork. A
> small
> > number of people have been flatly ignoring LOTS of highly technical and
> > passionate developers who have written vast amounts of code, built up the
> > Bitcoin user base, designed hardware and software, and yes built
> companies.
>
> I know you want scale bitcoin, as I said everyone here does. I think
> what you're experiencing is that you've had more luck explaining your
> pragmatic unilateral plan to non-technical people without peer review,
> and so not experienced the kind of huge pushback you are getting from
> the technical community.  The whole of bitcoin is immensely
> complicated such that it takes an uber-geek CS genius years to
> catchup, this is not a slight of any of the business people who are
> working hard to deploy Bitcoin into the world, its just complicated
> and therefore not easy to understand the game-theory, security,
> governance and distributed system thinking.  I have a comp sci PhD in
> distributed systems, implemented p2p network systems and have 2
> decades of applied crypto experience with a major interest in
> electronic cash crypto protocols, and it took me a several years to
> catchup and even I have a few hazy spots on low-level details, and I
> addictively into read everything I could find.  Realistically all of
> us are still learning, as bitcoin combines so many fields that it
> opens new possibilities.
>
> What I am expecting that yourself and Gavin are thinking is that
> you'll knock heads and force the issue and get to consensus.
>
> However I think you have seriously misjudged the risks and have not
> adequately explained them to companies you are talking with.  Indeed
> you do not fully seem to acknowledge the risks, nor to have a well
> thought out plan here of how you would actually manage it, nor the
> moral hazards of having a lone developer in hugely divisive
> circumstances in sole control of bitcoins running code.  Those are
> exactly the reasons for the code change governance process!
>
> Even though you are trying to help, the full result is you are not
> helping achieve anything by changing a constant and starting a
> unilateral hard-fork (not to trivialise the work of making a patch to
> do that).
>
> The work to even make the constant change be feasible was a result of
> 1000s of hours of work by others in the development community, that is
> emphatically and unilaterally telling you that hard-forks are hugely
> inadvisable.
>
> You are trying to break the code change governance security procedure
> that were put in place for good reason for the security of $3b of
> other peoples money, even if you have a pragmatic intent to help, this
> is flat out unacceptable.
>
> There are also security implications to what you are proposing, which
> I have heard you attempting to trivialise, that are core to Bitcoins
> security and core functionality.
>
> >  the overwhelming impression I get from a few
> > others here is that no, they don't want to scale Bitcoin. They already
> > decided it's a technological dead end.
>
> I think this is a significant mischaracterisation, and I think almost
> everybody is on board with a combination plan:
>
> 1. work to improve decentralisation (specific technical work already
> underway, and education)
> 2. create a plan to increase block-size in a slow fashion to not cause
> system shocks (eg like Jeff is proposing or some better variant)
> 3. work on actual algorithmic scaling
>
> In this way we can have throughput needed for scalability and security
> work to continue.
>
> As I said you can not scale a O(n^2) broadcast network by changing
> constants, you need algorithmic improvements.
>
> People are working on them already.  All of those 3 things are being
> actively worked on RIGHT NOW, and in the case of algorithmic scaling
> and improve decentralisation have been worked on for months.
>
> You may have done one useful thing which is to remind people that
> blocks are only 3x-4x below capacity such that we should look at it.
>
> But we can not work under duress of haste, nor unilateral ultimatums,
> this is the realm of human action that leads to moral hazard, and
> ironically reminds us of why Satoshi put the quote in the genesis
> block.
>
> Bitcoin is too complex a system with too much at stake to be making
> political hasty decisions, it would be negligent to act in such a way.
>
> Again please consider that you did your job, caused people to pay
> attention, but return to the process, submit a BIP, retract the
> unilateral hard-fork which is so dangerous and lets have things be
> calm, civil and collaborative in the technical zone of Bitcoin and not
> further alarm companies and investors.
>
> Adam
>
>
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