From: Adam Back <adam@cypherspace•org>
To: Christian Decker <decker.christian@gmail•com>
Cc: Bitcoin Dev <bitcoin-development@lists•sourceforge.net>
Subject: Re: [Bitcoin-development] Version bits proposal
Date: Thu, 28 May 2015 09:11:21 +0100 [thread overview]
Message-ID: <CALqxMTEc4K_YQo8aU1RwgJYasPs=bR8ORux8pyp0XDMTmNqNAg@mail.gmail.com> (raw)
In-Reply-To: <CALxbBHU3hT7+zOddryE0aW7otmE0OfQWi8WmFuhR_XZRK2VRNQ@mail.gmail.com>
Or as far as that goes, permuting (the non-dependent) transactions in
the block by permuting the internal merkle tree nodes at increasing
depths. (Dependent because transactions that depend on each other
have to come in-order; but one could eg put the n-1 of each n sequence
of in-order transactions in the left-half and unordered in the right
half.)
That makes the tree manipulations maximum depth independent, and even
transaction independent possibly - just need to know enough depth in
the tree of hashes that are permutation safe.
Adam
On 28 May 2015 at 08:51, Christian Decker <decker.christian@gmail•com> wrote:
> Agreed, there is no need to misuse the version field as well. There is more
> than enough variability you could roll in the merkle tree including and
> excluding transactions, and the scriptSig of the coinbase transaction, which
> also influences the merkle root.
>
> I have a fundamental dislike of retroactively changing semantics, and the
> version field should be used just for that: a version. I don't even
> particularly like flagging support for a fork in the version field, but
> since I have no better solution, count me as supporting Sipa's proposal. We
> definitely need a more comfortable way of rolling out new features.
>
> Regards,
> Chris
>
> On Thu, May 28, 2015 at 3:08 AM Patrick Strateman
> <patrick.strateman@gmail•com> wrote:
>>
>> There is absolutely no reason to do this.
>>
>> Any reasonable micro-controller can build merkle tree roots
>> significantly faster than is necessary.
>>
>> 1 Th/s walks the nonce range once every 4.3ms.
>>
>> The largest valid merkle trees are 14 nodes high.
>>
>> That translates to 28 SHA256 ops per 4.3ms or 6511 SHA256 ops/second.
>>
>> For reference an RPi 1 model B does 2451050 SHA256 ops/second.
>>
>> On 05/27/2015 03:52 PM, Sergio Lerner wrote:
>> > I like the idea but I think we should leave at least 16 bits of the
>> > version fixed as an extra-nonce.
>> > If we don't then miners may use them as a nonce anyway, and mess with
>> > the soft-fork voting system.
>> > My original proposal was this:
>> > https://github.com/bitcoin/bitcoin/pull/5102
>> >
>> > Best regards
>> >
>> >
>> >
>> > ------------------------------------------------------------------------------
>> > _______________________________________________
>> > Bitcoin-development mailing list
>> > Bitcoin-development@lists•sourceforge.net
>> > https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>>
>>
>>
>>
>> ------------------------------------------------------------------------------
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>
>
> ------------------------------------------------------------------------------
>
> _______________________________________________
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>
next prev parent reply other threads:[~2015-05-28 8:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-27 1:48 Pieter Wuille
2015-05-27 2:31 ` Douglas Roark
2015-05-27 3:46 ` Luke Dashjr
2015-05-27 3:51 ` Jorge Timón
2015-05-27 9:35 ` Tier Nolan
2015-05-27 10:15 ` Peter Todd
2015-05-27 11:26 ` Tier Nolan
2015-05-27 22:52 ` Sergio Lerner
2015-05-28 1:05 ` Patrick Strateman
2015-05-28 7:51 ` Christian Decker
2015-05-28 8:11 ` Adam Back [this message]
2015-06-01 14:50 ` Potter QQ
2015-05-27 10:15 ` Jorge Timón
2015-06-03 20:42 ` Pieter Wuille
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