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From: Btc Drak <btcdrak@gmail.com>
To: Gavin Andresen <gavinandresen@gmail.com>
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Weak block thoughts...
Date: Wed, 23 Sep 2015 17:07:31 +0100	[thread overview]
Message-ID: <CADJgMzt9xYdaVnvj96YicrcNGj_RWObKTFUsCeWUaP7Apnzwjw@mail.gmail.com> (raw)
In-Reply-To: <CABsx9T2+dG0AE+MgKRAU97KhkHTU1MuxXuwHKv3BgpJswZ5vVg@mail.gmail.com>

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For anyone who missed the discussions of weak blocks, here are the Scaling
Bitcoin's transcripts:

http://diyhpl.us/wiki/transcripts/scalingbitcoin/bitcoin-block-propagation-iblt-rusty-russell/

http://diyhpl.us/wiki/transcripts/scalingbitcoin/roundgroup-roundup-1/
(under Network Propagation).

On Wed, Sep 23, 2015 at 4:43 PM, Gavin Andresen via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> I've been thinking about 'weak blocks' and SPV mining, and it seems to me
> weak blocks will make things better, not worse, if we improve the mining
> code a little bit.
>
> First:  the idea of 'weak blocks' (hat tip to Rusty for the term) is for
> miners to pre-announce blocks that they're working on, before they've
> solved the proof-of-work puzzle. To prevent DoS attacks, assume that some
> amount of proof-of-work is done (hence the term 'weak block') to rate-limit
> how many 'weak block' messages are relayed across the network.
>
>
> Today, miners are incentivized to start mining an empty block as soon as
> they see a block with valid proof-of-work, because they want to spend as
> little time as possible mining a not-best chain.
>
> Imagine miners always pre-announce the blocks they're working on to their
> peers, and peers validate those 'weak blocks' as quickly as they are able.
>
> Because weak blocks are pre-validated, when a full-difficulty block based
> on a previously announced weak block is found, block propagation should be
> insanely fast-- basically, as fast as a single packet can be relayed across
> the network the whole network could be mining on the new block.
>
> I don't see any barrier to making accepting the full-difficulty block and
> CreateNewBlock() insanely fast, and if those operations take just a
> microsecond or three, miners will have an incentive to create blocks with
> fee-paying transactions that weren't in the last block, rather than mining
> empty blocks.
>
> .................
>
> A miner could try to avoid validation work by just taking a weak block
> announced by somebody else, replacing the coinbase and re-computing the
> merkle root, and then mining. They will be at a slight disadvantage to
> fully validating miners, though, because they WOULD have to mine empty
> blocks between the time a full block is found and a fully-validating miner
> announced their next weak block.
>
> .................
>
> Weak block announcements are great for the network; they give transaction
> creators a pretty good idea of whether or not their transactions are likely
> to be confirmed in the next block. And if we're smart about implementing
> them, they shouldn't increase bandwidth or CPU usage significantly, because
> all the weak blocks at a given point in time are likely to contain the same
> transactions.
>
> --
> --
> Gavin Andresen
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>

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  parent reply	other threads:[~2015-09-23 16:07 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-23 15:43 [bitcoin-dev] Weak block thoughts Gavin Andresen
2015-09-23 16:07 ` Bryan Bishop
2015-09-23 19:24   ` Gregory Maxwell
2015-09-23 21:37     ` Gavin Andresen
2015-09-23 22:16       ` Jonathan Toomim (Toomim Bros)
2015-09-24  1:11       ` Rusty Russell
2015-09-27  1:39       ` Gregory Maxwell
2015-09-27  9:42         ` Tier Nolan
2015-09-27 15:10           ` Kalle Rosenbaum
2015-09-27 19:50             ` Gregory Maxwell
2015-09-28  8:30               ` Kalle Rosenbaum
2015-09-28 13:30                 ` Jonathan Toomim (Toomim Bros)
2015-09-23 16:07 ` Btc Drak [this message]
2015-09-23 16:28 ` Peter R
2015-09-23 17:40   ` Gavin
2015-09-23 17:49     ` Peter R
2015-09-23 18:48 ` Tier Nolan
2015-09-24  1:32 ` Rusty Russell

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