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From: Luke Dashjr <luke@dashjr.org>
To: bitcoin-dev@lists.linuxfoundation.org, Tier Nolan <tier.nolan@gmail.com>
Subject: Re: [bitcoin-dev] Forcenet: an experimental network with a new header format
Date: Sat, 10 Dec 2016 21:41:57 +0000	[thread overview]
Message-ID: <201612102141.58206.luke@dashjr.org> (raw)
In-Reply-To: <CAE-z3OUpbUA2yviYoZouuZ0fp1WbbVdehWwNCd3juNsN-u9csA@mail.gmail.com>

On Saturday, December 10, 2016 9:29:09 PM Tier Nolan via bitcoin-dev wrote:
> On Sun, Dec 4, 2016 at 7:34 PM, Johnson Lau via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
> > Something not yet done:
> > 1. The new merkle root algorithm described in the MMHF BIP
> 
> Any new merkle algorithm should use a sum tree for partial validation and
> fraud proofs.

PR welcome.

> Is there something special about 216 bits?  I guess at most 448 bits total
> means only one round of SHA256.  16 bits for flags would give 216 for each
> child.

See https://github.com/luke-jr/bips/blob/bip-mmhf/bip-mmhf.mediawiki#Merkle_tree_algorithm

But yes, the 448 bits total target is to optimise the tree-building.

> Even better would be to make the protocol extendable.  Allow blocks to
> indicate new trees and legacy nodes would just ignore the extra ones.  If
> Bitcoin supported that then the segregated witness tree could have been
> added as a easier soft fork.

It already is. This is a primary goal of the new protocol.

> The sum-tree could be added later as an extra tree.

Adding new trees means more hashing to validate blocks, so it'd be better to 
keep it at a minimum.

Luke


  reply	other threads:[~2016-12-10 21:42 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-04 19:34 [bitcoin-dev] Forcenet: an experimental network with a new header format Johnson Lau
2016-12-04 20:00 ` adiabat
2016-12-04 20:37   ` Hampus Sjöberg
2016-12-05 11:58     ` Tom Zander
2016-12-14 11:01       ` Johnson Lau
2016-12-14 11:07         ` Luke Dashjr
2016-12-14 11:12           ` Johnson Lau
2016-12-14 11:11   ` Johnson Lau
2016-12-10 21:29 ` Tier Nolan
2016-12-10 21:41   ` Luke Dashjr [this message]
2016-12-11 16:40     ` Tier Nolan
2016-12-14 10:55       ` Johnson Lau
2016-12-14 12:52         ` Tier Nolan
2016-12-14 15:45           ` Johnson Lau
2016-12-14 16:26             ` Tier Nolan
2017-01-14 21:14 ` Johnson Lau
2017-01-28  2:32   ` Matt Corallo
2017-01-28  3:02     ` Matt Corallo
2017-01-28  7:28     ` Johnson Lau
2017-01-28 17:14       ` Matt Corallo

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