Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism

2015-06-11 Thread Mike Hearn

 If we assume that transactions are being dropped in an unpredictable way
 when blocks are full, knowing the network congestion *right now* is
 critical, and even then you just have to hope that someone who wants that
 space more than you do doesn't show up after you disconnect.


Yeah, my proposal is not intended to function correctly with full blocks,
as Bitcoin cannot work at all in such a state. It assumes that fees only
change slowly and that transactions are being cleared normally.
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Re: [Bitcoin-development] Is SourceForge still trustworthy enough to host this list?

2015-06-11 Thread Wladimir J. van der Laan
On Wed, Jun 10, 2015 at 09:36:23PM +0300, s7r wrote:
 The mail list is public, so it's not like the data on it is somehow
 sensitive. Sourcefoge is fine, it has a nice web UI where you can browse
 the message and sort/order them as you want, etc.
 
 Why would you want to move to a paid solution? And why would you want
 users to have to pay per message? This is the worst idea ever from my
 point of view. We want to encourage people to join the community, run
 full nodes, ask questions, come with solutions, ideas for improvements
 and so on. Everyone should read and write and contribute as much as
 possible with ideas in debates. You never know who can have bright ideas
 in some contexts.
 
 Bottom line is so far sourceforge handles the mail lists just fine. I
 don't see a single advantage another mail list provider / system could
 offer, except some headache and extra work for migration. The software
 distribution via sourcefoge was cancelled for obvious reasons which I
 fully understand and agree to, but it has nothing to do with the mail
 lists. We have way more important things to brainstorm about.

I completely agree here. I'm not against migration if a much better option 
comes along, but e.g. paying for another provider sounds like nonsense when 
sourceforge does this for free (with some minor annoyances - other providers 
will have their own).

Paying per message is far-fetched, something that could work in economic theory 
with perfectly spherical people in their perfectly efficient market. In 
practice the likely result would be a mailing list only used for advertisement 
and promotion, and technical discussion and release announcements would 
disappear.

BTW for people that *don't* like sourceforge's web archive UI there are some 
other options via gmane:

http://dir.gmane.org/gmane.comp.bitcoin.devel

Wladimir

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Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism

2015-06-11 Thread Tom Harding
On 6/11/2015 6:10 AM, Peter Todd wrote:
 On Wed, Jun 10, 2015 at 02:18:30PM -0700, Aaron Voisine wrote:
 The other complication is that this will tend to be a lagging indicator
 based on network congestion from the last time you connected. If we assume
 that transactions are being dropped in an unpredictable way when blocks are
 full, knowing the network congestion *right now* is critical, and even then
 you just have to hope that someone who wants that space more than you do
 doesn't show up after you disconnect.
 Hence the need for ways to increase fees on transactions after initial
 broadcast like replace-by-fee and child-pays-for-parent.

 Re: dropped in an unpredictable way - transactions would be dropped
 lowest fee/KB first, a completely predictable way.

Quite agreed.  Also, transactions with unconfirmed inputs should be 
among the first to get dropped, as discussed in the Dropped-transaction 
spam thread.  Like all policy rules, either of these works in 
proportion to its deployment.

Be advised that pull request #6068 emphasizes the view that the network 
will never have consistent mempool/relay policies, and on the contrary 
needs a framework that supports and encourages pluggable, generally 
parameterized policies that could (some might say should) conflict 
wildly with each other.

It probably doesn't matter that much.  Deploying a new policy still 
wouldn't be much easier than deploying a patched version.  I mean, 
nobody has proposed a policy rule engine yet (oops).



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Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism

2015-06-11 Thread Mike Hearn

  Re: dropped in an unpredictable way - transactions would be dropped
  lowest fee/KB first, a completely predictable way.

 Quite agreed.


No, Aaron is correct. It's unpredictable from the perspective of the user
sending the transaction, and as they are the ones picking the fees, that is
what matters.
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Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism

2015-06-11 Thread Nathan Wilcox
On Wed, Jun 10, 2015 at 2:03 PM, Peter Todd p...@petertodd.org wrote:

 On Wed, Jun 10, 2015 at 02:00:27PM -0600, Nathan Wilcox wrote:
  On Wed, Jun 10, 2015 at 1:19 PM, Aaron Voisine vois...@gmail.com
 wrote:
 
   It could be done by agreeing on a data format and encoding it in an
   op_return output in the coinbase transaction. If it catches on it could
   later be enforced with a soft fork.
  
  
  Sounds plausible, except SPV protocols would need to include this
 coinbase
  txn if it's going to help SPV clients. (Until a softfork is activated,
 SPV
  clients should not rely on this encoding, since until that time the
 results
  can be fabricated by individual miners.)

 Fee stats can always be fabricated by individual miners because fees can
 be paid out-of-band.


This is a point I hadn't considered carefully before. I don't understand
the marketplace here or why miners would want to move fees outside of
explicit inband fees. Implicit in this proposal is that the statistics only
cover in-band data, because that's the scope of consensus rules, and thus
the proposal is only as useful as the information of in-band fees is useful.

I've also noticed a detracting technical argument given a particular
tradeoff:

A Header-PoW-verifying client could still be given all transactions in a
recent block, from which it can see the in-band fees directly.  The
trade-off is the size of those transactions versus the need to alter any
consensus rules or do soft forks.

Notice how this trade-off's costs change with maximum block size.




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Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism

2015-06-11 Thread Aaron Voisine
 A Header-PoW-verifying client could still be given all transactions in a
recent block, from which it can see the in-band fees directly.

You don't know the fees paid by any given transaction unless you also have
all it's inputs. Transaction inputs do not include an amount. You could
however get the average fee-per-kb paid by all transactions in a block by
looking at the coinbase transaction, subtracting the block reward, and
dividing by the size of block minus the header.


Aaron Voisine
co-founder and CEO
breadwallet.com

On Thu, Jun 11, 2015 at 11:30 AM, Nathan Wilcox nat...@leastauthority.com
wrote:

 On Wed, Jun 10, 2015 at 2:03 PM, Peter Todd p...@petertodd.org wrote:

 On Wed, Jun 10, 2015 at 02:00:27PM -0600, Nathan Wilcox wrote:
  On Wed, Jun 10, 2015 at 1:19 PM, Aaron Voisine vois...@gmail.com
 wrote:
 
   It could be done by agreeing on a data format and encoding it in an
   op_return output in the coinbase transaction. If it catches on it
 could
   later be enforced with a soft fork.
  
  
  Sounds plausible, except SPV protocols would need to include this
 coinbase
  txn if it's going to help SPV clients. (Until a softfork is activated,
 SPV
  clients should not rely on this encoding, since until that time the
 results
  can be fabricated by individual miners.)

 Fee stats can always be fabricated by individual miners because fees can
 be paid out-of-band.


 This is a point I hadn't considered carefully before. I don't understand
 the marketplace here or why miners would want to move fees outside of
 explicit inband fees. Implicit in this proposal is that the statistics only
 cover in-band data, because that's the scope of consensus rules, and thus
 the proposal is only as useful as the information of in-band fees is useful.

 I've also noticed a detracting technical argument given a particular
 tradeoff:

 A Header-PoW-verifying client could still be given all transactions in a
 recent block, from which it can see the in-band fees directly.  The
 trade-off is the size of those transactions versus the need to alter any
 consensus rules or do soft forks.

 Notice how this trade-off's costs change with maximum block size.




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 1245bd2f5c99379ee76836227ded9c08324894faabc0d27f




 --
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 Least Authoritarian

 email: nat...@leastauthority.com
 twitter: @least_nathan
 PGP: 11169993 / AAAC 5675 E3F7 514C 67ED  E9C9 3BFE 5263 1116 9993

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[Bitcoin-development] Miners: You'll (very likely) need to upgrade your Bitcoin Core node soon to support BIP66

2015-06-11 Thread Peter Todd
Summary
---

The BIP66 soft-fork recently passed the 75% support threshold. This
means that 75% of the hashing power has upgraded to support BIP66; 25%
of the hashing power has not. Once 95% of the hashing power has
upgraded, blocks created by the 5% who have not upgraded will be
rejected.

If you operate a pool, solo-mine, or mine on p2pool you'll very likely
need to upgrade your Bitcoin Core node to support the BIP66 soft-fork,
or your blocks will be rejected. If you only sell your hashing power to
a centralized pool you do not need to do anything.


How does the Bitcoin protocol measure BIP66 support?


Miners that have upgraded to support BIP66 create blocks with the
version field set to 3; non-upgraded miners set the version to 2.
Bitcoin Core measures BIP66 support by counting how many blocks with
version = 3 exist in the blockchain within the last 1000 blocks.

If 750 out of the last 1000 blocks support BIP66, blocks with the
version set to = 3 that do not follow the BIP66 rules are rejected; if
950 out of the last 1000 blocks support BIP66, blocks with version  3
are rejected.


When will the 95% threshold be reached?
---

It's unknown exactly when the 95% threshold will be reached. The BIP34
soft-fork went from 75% to 95% support in a about two weeks, however
more or less time is possible; it's possible that the 95% threshold will
be reached in just a few days.


How can I monitor BIP66 adoption?
-

See Pieter Wuille's graphs:

http://bitcoin.sipa.be/ver-ever.png
http://bitcoin.sipa.be/ver-50k.png
http://bitcoin.sipa.be/ver-10k.png
http://bitcoin.sipa.be/ver-2k.png

The 'ever' and '50k' graphs show the 75% and 95% thresholds.


What software supports support BIP66?
-

Bitcoin Core releases later than v0.10.0 support BIP66.

In addition, v0.9.5 supports BIP66, however we recommend that you
upgrade to v0.10.2

If you run a pool, you may also need to upgrade your pool software as
well. For instance, eloipool versions prior to May 22nd 2015, git commit
f5f4ea636fb38f38e6d9a04aad1f04427556a4bc, do not support BIP66. (For
Eloipool, cb8a5e8fbb4bfdfe9e35f670082603caff65e1b2 is a clean merge that
should work for any branch more recent than 2013 April 6)

Solo miners and decentralised miners using GBT need to also update their
mining software to a currently supported version of BFGMiner to get
support for v3 blocks. The official BFGMiner binaries include this
update with 5.1.0, 4.10.2, and 3.10.9.


What is BIP66?
--

BIP66 - Strict DER signatures - is a soft-fork that tightens the rules
for signature verification, specifically the way that signatures are
encoded. The Bitcoin Core implementation currently relies on OpenSSL for
signature validation, which means it implicitly defines Bitcoin's block
validity rules. Unfortunately, OpenSSL is not designed for
consensus-critical behaviour (it does not guarantee bug-for-bug
compatibility between versions), and thus changes to it can - and have -
affected Bitcoin software. (see CVE-2014-8275)

By tightening these rules BIP66 reduces the risk that changes to OpenSSL
will cause forks in the Bitcoin blockchain, as seen previously by the
March 2013 fork. Secondly reducing our dependency on OpenSSL is a step
towards replacing OpenSSL with libsecp256k1, a signature validation
library from Pieter Wuille and Gregory Maxwell, that is designed for
consensus-critical applications, as well as being significantly faster
than OpenSSL.


Is it possible that the BIP66 soft-fork will not happen?


In theory yes, though it is unlikely and rejection of BIP66 would be a
very ugly process. Unfortunately the existing soft-fork mechanism
provides no mechanism for a soft-fork to expire, so once set in motion
there is no clean way to stop a soft-fork.

There is a proposal from Wuille/Maxwell/Todd, to reform how soft-forks
are adopted that aims to fix this issue, as well as allow multiple
soft-forks be adopted in parallel:

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

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