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From: Johnson Lau <jl2012@xbt.hk>
To: Natanael <natanael.l@gmail.com>
Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Anti-transaction replay in a hardfork
Date: Wed, 25 Jan 2017 15:21:57 +0800	[thread overview]
Message-ID: <45F53199-C8AC-4DD3-B746-D56F9F01946B@xbt.hk> (raw)
In-Reply-To: <CAAt2M1_cQTfaDyQkaixeFB5Ubi35fSOs9Ks74WZEehtFk__B3w@mail.gmail.com>

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Assuming Alice is paying Bob with an old style time-locked tx. Under your proposal, after the hardfork, Bob is still able to confirm the time-locked tx on both networks. To fulfil your new rules he just needs to send the outputs to himself again (with different tx format). But as Bob gets all the money on both forks, it is already a successful replay


> On 25 Jan 2017, at 15:15, Natanael <natanael.l@gmail.com> wrote:
> 
> 
> Den 25 jan. 2017 08:06 skrev "Johnson Lau" <jl2012@xbt.hk <mailto:jl2012@xbt.hk>>:
> What you describe is not a fix of replay attack. By confirming the same tx in both network, the tx has been already replayed. Their child txs do not matter.
> 
> Read it again. 
> 
> The validation algorithm would be extended so that the transaction can't be replayed, because replaying it in the other network REQUIRES a child transaction in the same block that is valid, a child transaction the is unique to the network. By doing this policy change simultaneously in both networks, old pre-signed transactions *can not be replayed by anybody but the owner* of the coins (as he must spend them immediately in the child transaction). 
> 
> It means that as soon as spent, the UTXO sets immediately and irrevocably diverges across the two networks. Which is the entire point, isn't it? 


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  reply	other threads:[~2017-01-25  7:22 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-24 14:33 [bitcoin-dev] Anti-transaction replay in a hardfork Johnson Lau
2017-01-24 18:52 ` Tom Harding
2017-01-25  4:03   ` Johnson Lau
2017-01-25 19:32     ` Tom Harding
2017-01-27 20:47       ` Johnson Lau
2017-01-27 22:11         ` Tom Harding
2017-01-25  1:22 ` Natanael
2017-01-25  7:05   ` Johnson Lau
2017-01-25  7:15     ` Natanael
2017-01-25  7:21       ` Johnson Lau [this message]
2017-01-25  7:29         ` Natanael
2017-01-25  7:42           ` Johnson Lau
2017-01-26  3:29 ` Matt Corallo
2017-01-26  7:03   ` Chris Priest
2017-01-26  7:14     ` Johnson Lau
2017-01-26  8:59       ` Chris Priest
2017-01-26  9:20         ` Johnson Lau
2017-01-26 10:55           ` Edmund Edgar
2017-01-26 15:58           ` Tom Harding
2017-01-26 17:21   ` Gavin Andresen
2017-01-26 17:41     ` Matt Corallo

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