[bitcoin-dev] BIP65 / CHECKLOCKTIMEVERIFY deployment

[bitcoin-dev] BIP65 / CHECKLOCKTIMEVERIFY deployment

[Peter Todd]

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BIP66 adoption is quite close to 95% and will likely be enforced for all
blocks in a few more days; now is time to think about how CLTV will be
deployed, particularly given its benefits to much-needed scalability
solutions such as payment channels.

While I'm both a fan and co-author of the Version bits BIP(1) proposal,
it hasn't been implemented yet, and the implementation will be
relatively complex compared to the previous soft-fork mechanism. I think
there is good reason to get CLTV deployed sooner, and I don't think we
have any lack of consensus on it. The CLTV code itself has been
extensively reviewed in the form of the "mempool-only" pull-req, has
been included in the Elements sidechain prototype by Mark Friedenbach,
has been running in production on Viacoin for six months, and has a few
working demos of its functionality implemented. It's also been famously
described as "What you thought nLockTime did until you actually tried to
use it."

To that end I'm proposing that we simply use the existing median block
version mechanism previously used for the nVersion=2 and nVersion=3
soft-forks for CLTV. This mechanism is well-tested and understood, and
would allow CLTV to be easily backported to v0.10.x (even 0.9.x) with
little risk for rapid deployment. In the event that another soft-fork is
proposed prior to BIP65, nVersion=4, enforcement, we do have the option
of setting in motion yet another soft-fork as the median mechanism only
requires forks to be serialized in sequence - it does not prevent
multiple soft-forks from being "in-flight" at the same time.

Thoughts? If there are no objections I'll go ahead and write that code,
using the same thresholds as BIP66.

1) https://www.mail-archive.com/bitcoin-development@lists.sourceforge.net/msg07863.html

-- 
'peter'[:-1]@petertodd.org
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Re: [bitcoin-dev] BIP65 / CHECKLOCKTIMEVERIFY deployment

[Eric Lombrozo]

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Please do it.
On Jun 25, 2015 3:33 PM, "Peter Todd" <pete@petertodd.org> wrote:

> BIP66 adoption is quite close to 95% and will likely be enforced for all
> blocks in a few more days; now is time to think about how CLTV will be
> deployed, particularly given its benefits to much-needed scalability
> solutions such as payment channels.
>
> While I'm both a fan and co-author of the Version bits BIP(1) proposal,
> it hasn't been implemented yet, and the implementation will be
> relatively complex compared to the previous soft-fork mechanism. I think
> there is good reason to get CLTV deployed sooner, and I don't think we
> have any lack of consensus on it. The CLTV code itself has been
> extensively reviewed in the form of the "mempool-only" pull-req, has
> been included in the Elements sidechain prototype by Mark Friedenbach,
> has been running in production on Viacoin for six months, and has a few
> working demos of its functionality implemented. It's also been famously
> described as "What you thought nLockTime did until you actually tried to
> use it."
>
> To that end I'm proposing that we simply use the existing median block
> version mechanism previously used for the nVersion=2 and nVersion=3
> soft-forks for CLTV. This mechanism is well-tested and understood, and
> would allow CLTV to be easily backported to v0.10.x (even 0.9.x) with
> little risk for rapid deployment. In the event that another soft-fork is
> proposed prior to BIP65, nVersion=4, enforcement, we do have the option
> of setting in motion yet another soft-fork as the median mechanism only
> requires forks to be serialized in sequence - it does not prevent
> multiple soft-forks from being "in-flight" at the same time.
>
> Thoughts? If there are no objections I'll go ahead and write that code,
> using the same thresholds as BIP66.
>
> 1)
> https://www.mail-archive.com/bitcoin-development@lists.sourceforge.net/msg07863.html
>
> --
> 'peter'[:-1]@petertodd.org
> 0000000000000000007fc13ce02072d9cb2a6d51fae41fefcde7b3b283803d24
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>

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Re: [bitcoin-dev] BIP65 / CHECKLOCKTIMEVERIFY deployment

[Tier Nolan]

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It would be possible to run a simplified version of the bits proposal,
until BIP 66 locks.

It's obviously not worth it at this point though, though it could be 1-2
weeks more.

Version 2 means neither option
Version 3 means BIP 66 only
Version 4 means CLTV only
Version 5 means both

If (Version 3 + version 5) > 95%, reject 2 & 4
If (Version 4 + version 5) > 95%, reject 2 & 3

For 2 options at the same time, this isn't much extra overhead.


On Fri, Jun 26, 2015 at 12:52 AM, Eric Lombrozo <elombrozo@gmail.com> wrote:

> Please do it.
> On Jun 25, 2015 3:33 PM, "Peter Todd" <pete@petertodd.org> wrote:
>
>> BIP66 adoption is quite close to 95% and will likely be enforced for all
>> blocks in a few more days; now is time to think about how CLTV will be
>> deployed, particularly given its benefits to much-needed scalability
>> solutions such as payment channels.
>>
>> While I'm both a fan and co-author of the Version bits BIP(1) proposal,
>> it hasn't been implemented yet, and the implementation will be
>> relatively complex compared to the previous soft-fork mechanism. I think
>> there is good reason to get CLTV deployed sooner, and I don't think we
>> have any lack of consensus on it. The CLTV code itself has been
>> extensively reviewed in the form of the "mempool-only" pull-req, has
>> been included in the Elements sidechain prototype by Mark Friedenbach,
>> has been running in production on Viacoin for six months, and has a few
>> working demos of its functionality implemented. It's also been famously
>> described as "What you thought nLockTime did until you actually tried to
>> use it."
>>
>> To that end I'm proposing that we simply use the existing median block
>> version mechanism previously used for the nVersion=2 and nVersion=3
>> soft-forks for CLTV. This mechanism is well-tested and understood, and
>> would allow CLTV to be easily backported to v0.10.x (even 0.9.x) with
>> little risk for rapid deployment. In the event that another soft-fork is
>> proposed prior to BIP65, nVersion=4, enforcement, we do have the option
>> of setting in motion yet another soft-fork as the median mechanism only
>> requires forks to be serialized in sequence - it does not prevent
>> multiple soft-forks from being "in-flight" at the same time.
>>
>> Thoughts? If there are no objections I'll go ahead and write that code,
>> using the same thresholds as BIP66.
>>
>> 1)
>> https://www.mail-archive.com/bitcoin-development@lists.sourceforge.net/msg07863.html
>>
>> --
>> 'peter'[:-1]@petertodd.org
>> 0000000000000000007fc13ce02072d9cb2a6d51fae41fefcde7b3b283803d24
>>
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev@lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>

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Re: [bitcoin-dev] BIP65 / CHECKLOCKTIMEVERIFY deployment

[Peter Todd]

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On Thu, Jun 25, 2015 at 06:33:44PM -0400, Peter Todd wrote:
> Thoughts? If there are no objections I'll go ahead and write that code,
> using the same thresholds as BIP66.

I've opened a pull-req to deploy CHECKLOCKTIMEVERIFY via the
IsSuperMajority() mechanism:

    https://github.com/bitcoin/bitcoin/pull/6351

    Final step towards CLTV deployment on mainnet.

    I've copied the logic and tests from the previous BIP66 (DERSIG)
    soft-fork line-by-line for ease of review; any code review applicable to
    BIP66 should be applicable to BIP65.

    Once merged I'll prepare a backport of the soft-fork logic for the
    v0.10.x branch as well.

-- 
'peter'[:-1]@petertodd.org
00000000000000000dbc12bdcb4d0a340272edd649d24849f86a20d075f0dba1

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Re: [bitcoin-dev] BIP65 / CHECKLOCKTIMEVERIFY deployment

[Pieter Wuille]

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On Sun, Jun 28, 2015 at 9:50 PM, Peter Todd <pete@petertodd.org> wrote:

> On Thu, Jun 25, 2015 at 06:33:44PM -0400, Peter Todd wrote:
> > Thoughts? If there are no objections I'll go ahead and write that code,
> > using the same thresholds as BIP66.
>
> I've opened a pull-req to deploy CHECKLOCKTIMEVERIFY via the
> IsSuperMajority() mechanism:
>
>     https://github.com/bitcoin/bitcoin/pull/6351
>
>     Final step towards CLTV deployment on mainnet.
>
>     I've copied the logic and tests from the previous BIP66 (DERSIG)
>     soft-fork line-by-line for ease of review; any code review applicable
> to
>     BIP66 should be applicable to BIP65.
>

ACK on merging using IsSuperMajority.

-- 
Pieter

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