Re: [bitcoin-dev] BIP: OP_BRIBVERIFY - the op code needed for Blind Merge Mined drivechains

[Adam Back via bitcoin-dev]

On 27 June 2017 at 22:20, Luke Dashjr via bitcoin-dev
 wrote:
> On Wednesday 28 June 2017 12:37:13 AM Chris Stewart via bitcoin-dev wrote:
>> BRIBEVERIFY redefines the existing NOP4 opcode. When executed, if the given
>> critical hash is included at the given vout index in the coinbase
>> transaction the script evaluates to true. Otherwise, the script will fail.
>>
>> This allows sidechains to be merged mined against
>> bitcoin without burdening bitcoin miners with extra resource requirements.
>
> I don't see how. It seems like the logical outcome from this is "whoever pays
> the most gets the next sidechain block"... That's not particularly useful for
> merge mining.

Maybe that's phrased badly but the point of the "blind merge mining"
is just that the sidechain fees are paid in main chain bitcoin (rather
than in sidechain bitcoin).

That means that a miner who solo mines the main chain could still mine
the sidechain by requesting a block-proposal from a trusted sidechain
fullnode.  The sidechain fullnode would actually pay the mainchain
fee, and pay itself the sidechain fees as part of the side-chain
block-proposal.

This was viewed as less centralising than forcing miners to directly
process sidechain blocks, which could in principle be bandwidth and
CPU expensive to process, construct and validate.

Adam
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Re: [bitcoin-dev] BIP: OP_BRIBVERIFY - the op code needed for Blind Merge Mined drivechains

[Luke Dashjr via bitcoin-dev]

On Wednesday 28 June 2017 12:37:13 AM Chris Stewart via bitcoin-dev wrote:
> BRIBEVERIFY redefines the existing NOP4 opcode. When executed, if the given
> critical hash is included at the given vout index in the coinbase
> transaction
> the script evaluates to true. Otherwise, the script will fail.
> 
> This allows sidechains to be merged mined against
> bitcoin without burdening bitcoin miners with extra resource requirements.

I don't see how. It seems like the logical outcome from this is "whoever pays 
the most gets the next sidechain block"... That's not particularly useful for 
merge mining.

> This enables sidechains in Bitcoin.

There are different kinds of sidechains...

Federated peg: this already works on Bitcoin.
SPV/SNARK peg: this isn't enabled by your BIP.
Drivechains: this isn't enabled by your BIP.

How do you say this enables any kind of sidechain?

> A new block rule is added which requires that the miner's coinbase reward
> be at index 0 in the coinbase transaction's output vector.
> 
> It also fixes the witness commitment output to be at index 1 of the
> coinbase transaction's output vector.

This is unacceptable, for reasons Greg already pointed out.

> This document is placed in the public domain.

Note that this is not acceptable for BIPs anymore.

https://github.com/bitcoin/bips/blob/master/bip-0002.mediawiki#BIP_licensing
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Re: [bitcoin-dev] BIP: OP_BRIBVERIFY - the op code needed for Blind Merge Mined drivechains

[Gregory Maxwell via bitcoin-dev]

On Wed, Jun 28, 2017 at 12:37 AM, Chris Stewart via bitcoin-dev
 wrote:
> A new block rule is added which requires that the miner's coinbase reward be
> at index 0 in the coinbase transaction's output vector.

This is an absurd restriction-- I hope it was not your intent to
directly ban P2Pool and probably any other form of decentralized or
less centralized mining pooling... but thats what doing that does.

> It also fixes the witness commitment output to be at index 1 of the coinbase 
> transaction's output vector.

This removes important flexibility that was intentionally preserved.
What happens when an additional commitment is needed for bitcoin?
must some sidechain be irreparably destroyed? looks like it in  your
proposal.

> For instance, the mimblewimble sidechain could correspond to index 2 of the 
> vector outputs on the coinbase transaction.

And what happens if index 1 isn't present? if index 35 is used must
there be 34 dummy outputs?

> This op code looks into the coinbase transaction's output vector at the given 
> index (which is derived from the sidechain id) and checks to see if the hash 
> in the block matches the hash inside of the BRIBEVERIFY progra

This is not monotone/reorg safe. It means that the output coins (if
any) are not equivalently fungible with other bitcoins (for, e.g. 100
blocks) because if there is a reorg this transaction cannot be
restored to the chain.  It's also impure and not compatible with
caching, which would be unfortunate and slow block propagation.
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Re: [bitcoin-dev] Miners forced to run non-core code in order to get segwit activated

[Erik Aronesty via bitcoin-dev]

There's a pull req to core already for part of it:

https://github.com/bitcoin/bitcoin/pull/10444




On Tue, Jun 27, 2017 at 12:31 PM, Jorge Timón via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> First the implementation, then the technical design (BIP)... will the
> analysis come after that?
> Will there be any kind of simulations of tje proposed size or will thag
> come only after activation on mainnet?
> I assume the very last step will be activation on testnet 3 ?
>
>
> On 27 Jun 2017 8:44 am, "Sergio Demian Lerner via bitcoin-dev" <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
> Currently the only implementation that fulfills the requirements of the
> NYA agreement is the segwit2x/btc1 implementation, which is being finalized
> this week.
>
> Segwit2mb does not fulfill the NYA agreement.
>
> I'm asking now the segwit2x development team when a BIP will be ready so
> that Core has the opportunity to evaluate the technical proposal.
>
>
>
>
> On Wed, Jun 21, 2017 at 1:05 AM, Jacob Eliosoff via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> Well, this Saturday's "Chinese roundtable" statement from a bunch of
>> miners (https://pastebin.com/b3St9VCF) says they intend "NYA" in the
>> coinbase as support for "the New York consensus SegWit2x program btc1 (
>> https://github.com/btc1)", whose code includes the (accelerated
>> 336-block) BIP 91 change.  So, other facts or interpretations could come to
>> light, but until they do we should probably assume that's what the "NYA"
>> (which just broke 80% over the last 24h) means.
>>
>>
>> On Tue, Jun 20, 2017 at 10:11 PM, Mark Friedenbach 
>> wrote:
>>
>>> 80% have set "NYA" in their coinbase string. We have no idea what that
>>> means. People are equating it to BIP 91 -- but BIP 91 did not exist at
>>> the time of the New York agreement, and differs from the actual text
>>> of the NYA in substantive ways. The "Segwit2MB" that existed at the
>>> time of the NYA, and which was explicitly referenced by the text is
>>> the proposal by Sergio Demian Lerner that was made to this mailing
>>> list on 31 March. The text of the NYA grants no authority for
>>> upgrading this proposal while remaining compliant with the agreement.
>>> This is without even considering the fact that in the days after the
>>> NYA there was disagreement among those who signed it as to what it
>>> meant.
>>>
>>> I feel it is a very dangerous and unwarranted assumption people are
>>> making that what we are seeing now is either 80% support for BIP-91 or
>>> for the code in the btc1 repo.
>>>
>>> On Tue, Jun 20, 2017 at 6:36 PM, Erik Aronesty  wrote:
>>> > # Jacob Eliosoff:
>>> >
>>> >>  will start orphaning non-bit-1 blocks before Aug 1, and we avoid a
>>> split.
>>> >
>>> > Correct.  There are 2 short activation periods in BIP91 either of which
>>> > would avoid a split.
>>> >
>>> > # Gregory Maxwell:
>>> >
>>> >> unclear to me _exactly_ what it would need to implement to be
>>> consistent.
>>> >
>>> > This is the relevant pull req to core:
>>> >
>>> > https://github.com/bitcoin/bitcoin/pull/10444
>>> >
>>> > Seems OK.  It's technically running now on testnet5.   I think it (or a
>>> > -bip148 option) should be merged as soon as feasible.
>>> >
>>> >> previously debunked "XT" and "Classic" hysteria.
>>> >
>>> > apples vs oranges, imo.   segwit is not a contentious feature.   the
>>> > "bundling" in segwit2x is, but that's not the issue here.   the issue
>>> is we
>>> > are indirectly requiring miners that strongly support segwit to install
>>> > consensus protocol changes outside of bitcoin's standard reference.
>>>  80% of
>>> > them have signaled they will do so.   these are uncharted waters.
>>> >
>>> >
>>> > On Tue, Jun 20, 2017 at 6:57 PM, Jacob Eliosoff via bitcoin-dev
>>> >  wrote:
>>> >>
>>> >> I could be wrong, but the latest BIP91 implementation (also included
>>> in
>>> >> Segwit2x) cuts the activation period to 336 blocks (2.33 days).
>>> (This has
>>> >> been updated at
>>> >> https://github.com/bitcoin/bips/blob/master/bip-0091.mediawiki.)  So
>>> if 80%
>>> >> of hashpower is actually running that code and signaling on bit 4 by
>>> July 25
>>> >> or so, then those 80+% will start orphaning non-bit-1 blocks before
>>> Aug 1,
>>> >> and we avoid a split.
>>> >>
>>> >> There may still be a few non-bit-1 blocks that get orphaned after Aug
>>> 1,
>>> >> because they're mined by old BIP141 nodes.  But it seems like very few
>>> >> miners won't be signaling either Segwit2x *or* BIP141 by then...
>>> >>
>>> >> Make sense?
>>> >>
>>> >>
>>> >> On Tue, Jun 20, 2017 at 6:48 PM, Mark Friedenbach <
>>> m...@friedenbach.org>
>>> >> wrote:
>>> >>>
>>> >>> Why do you say activation by August 1st is likely? That would
>>> require an
>>> >>> entire difficulty adjustment period with >=95% bit1 signaling. That
>>> seems a
>>> >>> tall order to organize in the scant few weeks remaining.

Re: [bitcoin-dev] Miners forced to run non-core code in order to get segwit activated

[Jorge Timón via bitcoin-dev]

First the implementation, then the technical design (BIP)... will the
analysis come after that?
Will there be any kind of simulations of tje proposed size or will thag
come only after activation on mainnet?
I assume the very last step will be activation on testnet 3 ?

On 27 Jun 2017 8:44 am, "Sergio Demian Lerner via bitcoin-dev" <
bitcoin-dev@lists.linuxfoundation.org> wrote:

Currently the only implementation that fulfills the requirements of the NYA
agreement is the segwit2x/btc1 implementation, which is being finalized
this week.

Segwit2mb does not fulfill the NYA agreement.

I'm asking now the segwit2x development team when a BIP will be ready so
that Core has the opportunity to evaluate the technical proposal.




On Wed, Jun 21, 2017 at 1:05 AM, Jacob Eliosoff via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Well, this Saturday's "Chinese roundtable" statement from a bunch of
> miners (https://pastebin.com/b3St9VCF) says they intend "NYA" in the
> coinbase as support for "the New York consensus SegWit2x program btc1 (
> https://github.com/btc1)", whose code includes the (accelerated
> 336-block) BIP 91 change.  So, other facts or interpretations could come to
> light, but until they do we should probably assume that's what the "NYA"
> (which just broke 80% over the last 24h) means.
>
>
> On Tue, Jun 20, 2017 at 10:11 PM, Mark Friedenbach 
> wrote:
>
>> 80% have set "NYA" in their coinbase string. We have no idea what that
>> means. People are equating it to BIP 91 -- but BIP 91 did not exist at
>> the time of the New York agreement, and differs from the actual text
>> of the NYA in substantive ways. The "Segwit2MB" that existed at the
>> time of the NYA, and which was explicitly referenced by the text is
>> the proposal by Sergio Demian Lerner that was made to this mailing
>> list on 31 March. The text of the NYA grants no authority for
>> upgrading this proposal while remaining compliant with the agreement.
>> This is without even considering the fact that in the days after the
>> NYA there was disagreement among those who signed it as to what it
>> meant.
>>
>> I feel it is a very dangerous and unwarranted assumption people are
>> making that what we are seeing now is either 80% support for BIP-91 or
>> for the code in the btc1 repo.
>>
>> On Tue, Jun 20, 2017 at 6:36 PM, Erik Aronesty  wrote:
>> > # Jacob Eliosoff:
>> >
>> >>  will start orphaning non-bit-1 blocks before Aug 1, and we avoid a
>> split.
>> >
>> > Correct.  There are 2 short activation periods in BIP91 either of which
>> > would avoid a split.
>> >
>> > # Gregory Maxwell:
>> >
>> >> unclear to me _exactly_ what it would need to implement to be
>> consistent.
>> >
>> > This is the relevant pull req to core:
>> >
>> > https://github.com/bitcoin/bitcoin/pull/10444
>> >
>> > Seems OK.  It's technically running now on testnet5.   I think it (or a
>> > -bip148 option) should be merged as soon as feasible.
>> >
>> >> previously debunked "XT" and "Classic" hysteria.
>> >
>> > apples vs oranges, imo.   segwit is not a contentious feature.   the
>> > "bundling" in segwit2x is, but that's not the issue here.   the issue
>> is we
>> > are indirectly requiring miners that strongly support segwit to install
>> > consensus protocol changes outside of bitcoin's standard reference.
>>  80% of
>> > them have signaled they will do so.   these are uncharted waters.
>> >
>> >
>> > On Tue, Jun 20, 2017 at 6:57 PM, Jacob Eliosoff via bitcoin-dev
>> >  wrote:
>> >>
>> >> I could be wrong, but the latest BIP91 implementation (also included in
>> >> Segwit2x) cuts the activation period to 336 blocks (2.33 days).  (This
>> has
>> >> been updated at
>> >> https://github.com/bitcoin/bips/blob/master/bip-0091.mediawiki.)  So
>> if 80%
>> >> of hashpower is actually running that code and signaling on bit 4 by
>> July 25
>> >> or so, then those 80+% will start orphaning non-bit-1 blocks before
>> Aug 1,
>> >> and we avoid a split.
>> >>
>> >> There may still be a few non-bit-1 blocks that get orphaned after Aug
>> 1,
>> >> because they're mined by old BIP141 nodes.  But it seems like very few
>> >> miners won't be signaling either Segwit2x *or* BIP141 by then...
>> >>
>> >> Make sense?
>> >>
>> >>
>> >> On Tue, Jun 20, 2017 at 6:48 PM, Mark Friedenbach <
>> m...@friedenbach.org>
>> >> wrote:
>> >>>
>> >>> Why do you say activation by August 1st is likely? That would require
>> an
>> >>> entire difficulty adjustment period with >=95% bit1 signaling. That
>> seems a
>> >>> tall order to organize in the scant few weeks remaining.
>> >>>
>> >>> On Jun 20, 2017, at 3:29 PM, Jacob Eliosoff via bitcoin-dev
>> >>>  wrote:
>> >>>
>> >>> If segwit is activated before Aug 1, as now seems likely, there will
>> be
>> >>> no split that day.  But if activation is via Segwit2x (also likely),
>> and at
>> >>> least some nodes do & some don't 

Re: [bitcoin-dev] Miners forced to run non-core code in order to get segwit activated

[Sergio Demian Lerner via bitcoin-dev]

Currently the only implementation that fulfills the requirements of the NYA
agreement is the segwit2x/btc1 implementation, which is being finalized
this week.

Segwit2mb does not fulfill the NYA agreement.

I'm asking now the segwit2x development team when a BIP will be ready so
that Core has the opportunity to evaluate the technical proposal.




On Wed, Jun 21, 2017 at 1:05 AM, Jacob Eliosoff via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Well, this Saturday's "Chinese roundtable" statement from a bunch of
> miners (https://pastebin.com/b3St9VCF) says they intend "NYA" in the
> coinbase as support for "the New York consensus SegWit2x program btc1 (
> https://github.com/btc1)", whose code includes the (accelerated
> 336-block) BIP 91 change.  So, other facts or interpretations could come to
> light, but until they do we should probably assume that's what the "NYA"
> (which just broke 80% over the last 24h) means.
>
>
> On Tue, Jun 20, 2017 at 10:11 PM, Mark Friedenbach 
> wrote:
>
>> 80% have set "NYA" in their coinbase string. We have no idea what that
>> means. People are equating it to BIP 91 -- but BIP 91 did not exist at
>> the time of the New York agreement, and differs from the actual text
>> of the NYA in substantive ways. The "Segwit2MB" that existed at the
>> time of the NYA, and which was explicitly referenced by the text is
>> the proposal by Sergio Demian Lerner that was made to this mailing
>> list on 31 March. The text of the NYA grants no authority for
>> upgrading this proposal while remaining compliant with the agreement.
>> This is without even considering the fact that in the days after the
>> NYA there was disagreement among those who signed it as to what it
>> meant.
>>
>> I feel it is a very dangerous and unwarranted assumption people are
>> making that what we are seeing now is either 80% support for BIP-91 or
>> for the code in the btc1 repo.
>>
>> On Tue, Jun 20, 2017 at 6:36 PM, Erik Aronesty  wrote:
>> > # Jacob Eliosoff:
>> >
>> >>  will start orphaning non-bit-1 blocks before Aug 1, and we avoid a
>> split.
>> >
>> > Correct.  There are 2 short activation periods in BIP91 either of which
>> > would avoid a split.
>> >
>> > # Gregory Maxwell:
>> >
>> >> unclear to me _exactly_ what it would need to implement to be
>> consistent.
>> >
>> > This is the relevant pull req to core:
>> >
>> > https://github.com/bitcoin/bitcoin/pull/10444
>> >
>> > Seems OK.  It's technically running now on testnet5.   I think it (or a
>> > -bip148 option) should be merged as soon as feasible.
>> >
>> >> previously debunked "XT" and "Classic" hysteria.
>> >
>> > apples vs oranges, imo.   segwit is not a contentious feature.   the
>> > "bundling" in segwit2x is, but that's not the issue here.   the issue
>> is we
>> > are indirectly requiring miners that strongly support segwit to install
>> > consensus protocol changes outside of bitcoin's standard reference.
>>  80% of
>> > them have signaled they will do so.   these are uncharted waters.
>> >
>> >
>> > On Tue, Jun 20, 2017 at 6:57 PM, Jacob Eliosoff via bitcoin-dev
>> >  wrote:
>> >>
>> >> I could be wrong, but the latest BIP91 implementation (also included in
>> >> Segwit2x) cuts the activation period to 336 blocks (2.33 days).  (This
>> has
>> >> been updated at
>> >> https://github.com/bitcoin/bips/blob/master/bip-0091.mediawiki.)  So
>> if 80%
>> >> of hashpower is actually running that code and signaling on bit 4 by
>> July 25
>> >> or so, then those 80+% will start orphaning non-bit-1 blocks before
>> Aug 1,
>> >> and we avoid a split.
>> >>
>> >> There may still be a few non-bit-1 blocks that get orphaned after Aug
>> 1,
>> >> because they're mined by old BIP141 nodes.  But it seems like very few
>> >> miners won't be signaling either Segwit2x *or* BIP141 by then...
>> >>
>> >> Make sense?
>> >>
>> >>
>> >> On Tue, Jun 20, 2017 at 6:48 PM, Mark Friedenbach <
>> m...@friedenbach.org>
>> >> wrote:
>> >>>
>> >>> Why do you say activation by August 1st is likely? That would require
>> an
>> >>> entire difficulty adjustment period with >=95% bit1 signaling. That
>> seems a
>> >>> tall order to organize in the scant few weeks remaining.
>> >>>
>> >>> On Jun 20, 2017, at 3:29 PM, Jacob Eliosoff via bitcoin-dev
>> >>>  wrote:
>> >>>
>> >>> If segwit is activated before Aug 1, as now seems likely, there will
>> be
>> >>> no split that day.  But if activation is via Segwit2x (also likely),
>> and at
>> >>> least some nodes do & some don't follow through with the HF 3mo later
>> >>> (again, likely), agreed w/ Greg that *then* we'll see a split -
>> probably in
>> >>> Sep/Oct.  How those two chains will match up and how the split will
>> play out
>> >>> is anyone's guess...
>> >>>
>> >>>
>> >>>
>> >>> On Jun 20, 2017 6:16 PM, "Hampus Sjöberg via bitcoin-dev"
>> >>>  wrote:
>> >>>
>>