From: Peter Todd <pete@petertodd•org>
To: Mike Hearn <hearn@vinumeris•com>
Cc: Bitcoin Dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Let's deploy BIP65 CHECKLOCKTIMEVERIFY!
Date: Mon, 28 Sep 2015 09:21:27 -0400 [thread overview]
Message-ID: <20150928132127.GA4829@savin.petertodd.org> (raw)
In-Reply-To: <CA+w+GKRCVr-9TVk66utp7xLRgTxNpxYoj3XQE-6y_N8JS6eO6Q@mail.gmail.com>
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On Mon, Sep 28, 2015 at 12:48:57PM +0200, Mike Hearn wrote:
> There is *no* consensus on using a soft fork to deploy this feature. It
> will result in the same problems as all the other soft forks - SPV wallets
> will become less reliable during the rollout period. I am against that, as
> it's entirely avoidable.
>
> Make it a hard fork and my objection will be dropped.
>
> Until then, as there is no consensus, you need to do one of two things:
>
> 1) Drop the "everyone must agree to make changes" idea that people here
> like to peddle, and do it loudly, so everyone in the community is correctly
> informed
>
> 2) Do nothing
Hmm? You didn't quote any of my email, so I'll remind you what I did say
we had consensus about:
2) We have consensus on the semantics of the CLTV opcode
and
3) We have consensus that Bitcoin should adopt CLTV
The broad peer review and discussion that got #6124 merged is a clear
sign that we expect CLTV to be eventually adopted. __The question isn't
if CLTV should be added to the Bitcoin protocol, but rather when.__
(emphasis mine)
Both those statements of consensus are *not* about how CLTV is to be
deployed. I did discuss deployment later:
6) We have the __necessary consensus__ to deploy CLTV via IsSuperMajority()
The various "nVersion bits" proposals - which I am a co-author of - have
the primary advantage of being able to cleanly deal with the case where
a soft-fork fails to get adopted. However, we do have broad consensus,
including across all sides of the blocksize debate, that CLTV should be
adopted. __The risk of CLTV failing to get miner adoption, and thus
blocking other soft-forks, is very low.__
I probably could have worded this section a bit more clearly; when I say
"necessary consensus" I'm referring to the consensus required for a
soft-fork deployment. At minimum a simple majority of hashing power -
your approval isn't required.
For a safe soft-fork, we'd like a super majority of miners to be on
board. For a IsSuperMajority() soft-fork - as opposed to nVersion bits -
we also need the probability of the soft-fork being rejected to be very
low. To achieve that, having consensus that CLTV is a good idea is the
best situation to be in. But that's not to say that a few dissenting
voices should be seen as a blocker to progress - rather is just makes
the deployment a bit more risky, being a sign that the consensus may
change in the future, with the soft-fork being later rejected. For
example strong objections by a respected Bitcoin developer who has made
significant contributions to the consensus codebase and protocol
development would be a strong sign that a IsSuperMajority() soft-fork
might fail, and deployment via nVersion bits is probably a better
approach. Fortunately we're not in that situation.
Hard-forks are a very different situation, with significantly more need
for very broad consensus, but that's been well discussed elsewhere.
I have three questions to you:
1) Do you agree that CLTV should be added to the Bitcoin protocol?
Ignoring the question how exactly it is added, hard-fork or soft-fork.
2) Will you add a IsSuperMajority() CLTV soft-fork to Bitcoin XT if it
is added to Bitcoin Core?
If you refuse to do this the risk of the soft-fork is increased a bit,
although miner support for XT has remained extremely low, and the 95%
switch-over threshold has a significant margin for error. (there's a 75%
threshold to consider as well, however as XT has adopted my pull-req
#5000 - Discourage NOPs reserved for soft-fork upgrades - those miners
will only produce valid blocks under CLTV rules)
3) Will you add soft-fork detection to bitcoinj, to allow SPV clients to
detect advertised soft-forks and correctly handle them?
Notably, if you do this your objections against soft-forks will be met,
as the behavior of a SPV client with soft-fork detection during a
soft-fork will be identical to that client during a hard-fork. In
particular, the SPV client will correct reject invalid blocks, and
continue to follow only the longest valid chain. (modulo unadvertised
forks of course, an inherently unavoidable problem with the SPV security
model) Secondly, that code should also detect forks it doesn't know
about - as is done in Bitcoin Core already - and warn the user.
--
'peter'[:-1]@petertodd.org
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next prev parent reply other threads:[~2015-09-28 13:21 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-27 18:50 Peter Todd
2015-09-27 20:26 ` jl2012
2015-09-27 20:27 ` Peter Todd
2015-09-27 20:27 ` Mark Friedenbach
2015-09-27 20:41 ` Btc Drak
2015-09-28 10:10 ` s7r
2015-09-28 10:48 ` Mike Hearn
2015-09-28 11:00 ` Adam Back
2015-09-28 11:40 ` Mike Hearn
2015-09-28 12:20 ` Eric Lombrozo
2015-09-28 12:26 ` Mike Hearn
2015-09-28 12:44 ` Eric Lombrozo
2015-09-28 12:54 ` Mike Hearn
2015-09-29 6:17 ` Eric Lombrozo
2015-09-29 12:02 ` Mike Hearn
2015-09-28 14:05 ` Btc Drak
2015-09-28 14:17 ` Mike Hearn
2015-09-28 21:12 ` odinn
2015-09-28 22:16 ` Dave Scotese
2015-09-28 11:04 ` Eric Lombrozo
2015-09-28 12:47 ` Tier Nolan
2015-09-28 13:01 ` Gavin Andresen
2015-09-28 13:28 ` Peter Todd
2015-09-28 13:43 ` Gavin Andresen
2015-09-28 14:14 ` Peter Todd
2015-09-28 13:21 ` Peter Todd [this message]
2015-09-28 13:41 ` Mike Hearn
2015-09-28 14:29 ` Peter Todd
2015-09-28 14:33 ` Mike Hearn
2015-09-28 14:43 ` Peter Todd
2015-09-28 14:51 ` Mike Hearn
2015-09-28 15:05 ` Peter Todd
2015-09-28 15:38 ` Mike Hearn
2015-09-28 16:52 ` jl2012
2015-09-28 17:14 ` Mike Hearn
2015-09-28 23:17 ` Jorge Timón
2015-09-29 12:07 ` Mike Hearn
2015-09-29 15:09 ` [bitcoin-dev] Why soft-forks? was: " Santino Napolitano
2015-09-29 13:30 ` [bitcoin-dev] " Jonathan Toomim (Toomim Bros)
2015-09-29 15:59 ` jl2012
2015-09-29 19:54 ` odinn
2015-09-29 18:31 ` Gregory Maxwell
2015-09-30 17:11 ` Mike Hearn
2015-09-30 17:58 ` Jorge Timón
2015-10-01 14:23 ` Tom Harding
2015-09-30 18:15 ` Adam Back
2015-09-30 19:26 ` Jeff Garzik
2015-09-30 19:56 ` Mike Hearn
2015-09-30 20:37 ` Jorge Timón
2015-09-30 21:06 ` Mike Hearn
2015-09-30 22:14 ` Jorge Timón
2015-10-01 0:11 ` Jorge Timón
2015-09-30 22:17 ` Jeff Garzik
2015-09-30 23:25 ` Gregory Maxwell
2015-09-30 20:15 ` Gregory Maxwell
2015-09-30 21:01 ` Mike Hearn
2015-09-30 22:59 ` Gregory Maxwell
2015-10-01 4:08 ` [bitcoin-dev] Crossing the line? [Was: Re: Let's deploy BIP65 CHECKLOCKTIMEVERIFY!] Tao Effect
2015-10-01 16:39 ` Jeff Garzik
2015-10-01 20:17 ` Milly Bitcoin
2015-10-02 12:23 ` Mike Hearn
2015-10-02 13:14 ` jl2012
2015-10-02 14:10 ` Marcel Jamin
2015-10-02 16:37 ` Gregory Maxwell
2015-10-07 15:00 ` [bitcoin-dev] Let's deploy BIP65 CHECKLOCKTIMEVERIFY! Anthony Towns
2015-10-07 15:46 ` Jonathan Toomim (Toomim Bros)
2015-10-07 16:02 ` Eric Lombrozo
2015-10-07 16:25 ` Eric Lombrozo
2015-10-07 16:26 ` Jonathan Toomim (Toomim Bros)
2015-10-07 16:38 ` Anthony Towns
2015-10-10 7:23 ` Anthony Towns
2015-10-12 7:02 ` digitsu
2015-10-12 16:33 ` Anthony Towns
2015-10-12 17:06 ` Anthony Towns
2015-10-13 0:08 ` digitsu
2015-09-29 20:03 ` Wladimir J. van der Laan
2015-09-30 4:05 ` Rusty Russell
2015-09-30 6:19 ` Adam Back
2015-09-30 12:30 ` Mike Hearn
2015-09-30 15:55 ` Jorge Timón
2015-09-30 19:17 ` John Winslow
2015-10-01 0:06 ` Rusty Russell
2015-09-30 17:14 ` Adam Back
2015-10-01 0:04 ` Rusty Russell
2015-10-02 1:57 NotMike Hearn
2015-10-02 2:12 ` GC
2015-10-05 10:59 ` Mike Hearn
2015-10-05 11:23 ` Jeff Garzik
2015-10-05 11:28 ` Mike Hearn
2015-10-05 12:04 ` Jorge Timón
2015-10-05 12:08 ` Clément Elbaz
2015-10-05 12:16 ` Jorge Timón
2015-10-05 12:29 ` Clément Elbaz
2015-10-05 15:42 ` Jorge Timón
2015-10-05 12:10 ` Mike Hearn
2015-10-05 15:33 ` Jorge Timón
2015-10-05 16:46 ` Mike Hearn
2015-10-06 6:20 ` Anthony Towns
2015-10-07 6:13 ` Micha Bailey
2015-10-05 13:29 ` Jorge Timón
2015-10-05 13:24 ` Jorge Timón
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