Message-ID: <54EA0571.4050107@thinlink.com>
Date: Sun, 22 Feb 2015 08:36:01 -0800
From: Tom Harding <tomh@thinlink.com>
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To: Peter Todd <pete@petertodd.org>
References: <20150212064719.GA6563@savin.petertodd.org>
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Cc: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] replace-by-fee v0.10.0rc4
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On 2/11/2015 10:47 PM, Peter Todd wrote:
> My replace-by-fee patch is now available for the v0.10.0rc4 release:
>
>      https://github.com/petertodd/bitcoin/tree/replace-by-fee-v0.10.0rc4
>

This patch immediately simplifies successful double-spends of 
unconfirmed transactions.  But the idea that it "gives a path to making 
zeroconf transactions economically secure" is quite dubious.

* You don't provide sufficient means to detect and relay double-spends, 
which is necessary to trigger a scorched-earth reaction.  Not all 
double-spends will conform to your replacement rules.

   * Maybe XT nodes would help to overcome this.  But meanwhile, in the 
ANYONECANPAY design, Bob's replacement is a triple-spend.  Even XT nodes 
won't relay it.

* It's unclear when, if ever, any senders/receivers will actually try to 
use scorched-earth as a double-spend deterrent.


Also, this patch significantly weakens DoS protections:

* It removes the early conflict check, making all conflict processing 
more expensive

   * There is no attempt to protect against the same transaction being 
continually replaced with the fee bumped by a minimal amount.