Re: [bitcoin-dev] Forcenet: an experimental network with a new header format

From: Tier Nolan <tier.nolan@gmail.com>
To: Johnson Lau <jl2012@xbt.hk>
Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Forcenet: an experimental network with a new header format
Date: Wed, 14 Dec 2016 12:52:14 +0000	[thread overview]
Message-ID: <CAE-z3OWEkwuxu+LiT1VsWDBnnoi5pQHDDiiKpi7i8oDOtPrB4A@mail.gmail.com> (raw)
In-Reply-To: <02E75CD7-24A8-4E2F-9466-B5497D0B77F8@xbt.hk>

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On Wed, Dec 14, 2016 at 10:55 AM, Johnson Lau <jl2012@xbt.hk> wrote:

> In a sum tree, however, since the nSigOp is implied, any redefinition
> requires either a hardfork or a new sum tree (and the original sum tree
> becomes a placebo for old nodes. So every softfork of this type creates a
> new tree)
>

That's a good point.

> The only way to fix this is to explicitly commit to the weight and nSigOp,
> and the committed value must be equal to or larger than the real value.
> Only in this way we could redefine it with softfork. However, that means
> each tx will have an overhead of 16 bytes (if two int64 are used)
>

The weight and sigop count could be transmitted as variable length
integers.  That would be around 2 bytes for the sigops and 3 bytes for the
weight, per transaction.

It would mean that the block format would have to include the raw
transaction, "extra"/tree information and witness data for each transaction.

On an unrelated note, the two costs could be combined into a unified cost.
For example, a sigop could have equal cost to 250 bytes.  This would make
it easier for miners to decide what to charge.

On the other hand, CPU cost and storage/network costs are not completely
interchangeable.

Is there anything that would need to be summed fees, raw tx size, weight
and sigops that the greater or equal rule wouldn't cover?

On 12 Dec 2016, at 00:40, Tier Nolan via bitcoin-dev <bitcoin-dev@lists.
linuxfoundation.org> wrote:

On Sat, Dec 10, 2016 at 9:41 PM, Luke Dashjr <luke@dashjr.org> wrote:

> On Saturday, December 10, 2016 9:29:09 PM Tier Nolan via bitcoin-dev wrote:
> > Any new merkle algorithm should use a sum tree for partial validation and
> > fraud proofs.
>
> PR welcome.
>

Fair enough.  It is pretty basic.

https://github.com/luke-jr/bips/pull/2

It sums up sigops, block size, block cost (that is "weight" right?) and
fees.
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