public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Gregory Maxwell <greg@xiph•org>
To: ZmnSCPxj <ZmnSCPxj@protonmail•com>
Cc: Bitcoin Dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Rolling UTXO set hashes
Date: Mon, 15 May 2017 23:59:58 +0000	[thread overview]
Message-ID: <CAAS2fgTif+Y6VzFG+w7W+CY1+D_roCqGyy392qB2KcDPGpVeiw@mail.gmail.com> (raw)
In-Reply-To: <CT3GNfkLsQJyM0EmWXc3HBmnW1h2iptP0SohZnXZfZPffoVmcofD8fs_E3kV5PuFL0pQSQwwk_FyR-8-wdANf15NE8UElNWqcEcc5Ql3n8M=@protonmail.com>

On Mon, May 15, 2017 at 11:04 PM, ZmnSCPxj via bitcoin-dev
<bitcoin-dev@lists•linuxfoundation.org> wrote:
> transactions is in the header, which would let lite nodes download a UTXO
> set from any full node and verify it by verifying only block headers
> starting from genesis.

Ya, lite nodes with UTXO sets are one of the the oldest observed
advantages of a commitment to the UTXO data:

https://bitcointalk.org/index.php?topic=21995.0

But it requires a commitment. And for most of the arguments for those
you really want compact membership proofs.  The recent rise in
interest in full block lite clients (for privacy reasons), perhaps
complements the membership proofless usage.

Pieter describes some uses for doing something like this without a
commitment.  In my view, it's more interesting to first gain
experience with an operation without committing to it (which is a
consensus change and requires more care and consideration, which are
easier if people have implementation experience).

> rather than merkle tree root of transactions is in the header,

For audibility and engineering reasons it would need to be be in
addition to rather than rather than, because the proof of work needs
to commit to the witness data (in that kind of flip, the transactions
themselves become witnesses for UTXO deltas) or you get trivial DOS
attacks where people provide malleated blocks that have invalid
witnesses.


  reply	other threads:[~2017-05-16  0:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-15 20:01 Pieter Wuille
2017-05-15 20:53 ` Peter R
2017-05-15 23:04 ` ZmnSCPxj
2017-05-15 23:59   ` Gregory Maxwell [this message]
2017-05-16  0:15     ` ZmnSCPxj
2017-05-16 11:01     ` Peter Todd
2017-05-16 18:17       ` Pieter Wuille
2017-05-16 18:20         ` Gregory Maxwell
2017-05-23  4:47           ` Rusty Russell
2017-05-23 20:43             ` Pieter Wuille

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAAS2fgTif+Y6VzFG+w7W+CY1+D_roCqGyy392qB2KcDPGpVeiw@mail.gmail.com \
    --to=greg@xiph$(echo .)org \
    --cc=ZmnSCPxj@protonmail$(echo .)com \
    --cc=bitcoin-dev@lists$(echo .)linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox