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From: jl2012@xbt.hk
To: "Jonathan Toomim (Toomim Bros)" <j@toom.im>
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Let's deploy BIP65 CHECKLOCKTIMEVERIFY!
Date: Tue, 29 Sep 2015 11:59:05 -0400	[thread overview]
Message-ID: <5e90be1b8f85cd46ed20eae84c062702@xbt.hk> (raw)
In-Reply-To: <40B097BA-A389-4C46-B5DE-2EC4738086BA@toom.im>

Jonathan Toomim (Toomim Bros) via bitcoin-dev 於 2015-09-29 09:30 寫到:
> SPV clients will appear to behave normally, and
> will continue to show new transactions and get confirmations in a
> timely fashion. However, they will be systematically susceptible to
> attack from double-spends that attempt to spend funds in a way that
> the upgraded nodes will reject. These transactions will appear to get
> 1 confirmation, then regress to zero conf, every single time. These
> attacks can be performed for as long as someone mines with the old
> version.

1. Who told you to accept 1-confirmation tx? Satoshi recommended 6 
confirmations in the whitepaper. Take your own risk if you do not follow 
his advice.

2. This is true only if your SPV client naively follows the longest 
chain without even looking at the block version. This might be good 
enough for the 1st generation SPV client, but future generations should 
at least have basic fraud detecting mechanism.



> If an attacker thinks he could get more than 25 BTC of
> double-spends per block, he might even choose to mine with the
> obsolete version in order to get predictable orphans and to trick SPV
> clients and fully verifying wallets on the old version.

This point is totally irrelevant. No matter there is a softfork or not, 
SPV users are always vulnerable to such double-spending attack if they 
blindly follow the longest chain AND accept 1-confirmation. The fiat 
currency system might be safer for them.


  reply	other threads:[~2015-09-29 15:59 UTC|newest]

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-27 18:50 [bitcoin-dev] Let's deploy BIP65 CHECKLOCKTIMEVERIFY! Peter Todd
2015-09-27 20:26 ` jl2012
2015-09-27 20:27   ` Peter Todd
2015-09-27 20:27 ` Mark Friedenbach
2015-09-27 20:41 ` Btc Drak
2015-09-28 10:10 ` s7r
2015-09-28 10:48 ` Mike Hearn
2015-09-28 11:00   ` Adam Back
2015-09-28 11:40     ` Mike Hearn
2015-09-28 12:20       ` Eric Lombrozo
2015-09-28 12:26         ` Mike Hearn
2015-09-28 12:44           ` Eric Lombrozo
2015-09-28 12:54             ` Mike Hearn
2015-09-29  6:17               ` Eric Lombrozo
2015-09-29 12:02                 ` Mike Hearn
2015-09-28 14:05       ` Btc Drak
2015-09-28 14:17         ` Mike Hearn
2015-09-28 21:12     ` odinn
2015-09-28 22:16       ` Dave Scotese
2015-09-28 11:04   ` Eric Lombrozo
2015-09-28 12:47   ` Tier Nolan
2015-09-28 13:01   ` Gavin Andresen
2015-09-28 13:28     ` Peter Todd
2015-09-28 13:43       ` Gavin Andresen
2015-09-28 14:14         ` Peter Todd
2015-09-28 13:21   ` Peter Todd
2015-09-28 13:41     ` Mike Hearn
2015-09-28 14:29       ` Peter Todd
2015-09-28 14:33         ` Mike Hearn
2015-09-28 14:43           ` Peter Todd
2015-09-28 14:51             ` Mike Hearn
2015-09-28 15:05               ` Peter Todd
2015-09-28 15:38                 ` Mike Hearn
2015-09-28 16:52                   ` jl2012
2015-09-28 17:14                     ` Mike Hearn
2015-09-28 23:17                       ` Jorge Timón
2015-09-29 12:07                         ` Mike Hearn
2015-09-29 15:09                           ` [bitcoin-dev] Why soft-forks? was: " Santino Napolitano
2015-09-29 13:30             ` [bitcoin-dev] " Jonathan Toomim (Toomim Bros)
2015-09-29 15:59               ` jl2012 [this message]
2015-09-29 19:54                 ` odinn
2015-09-29 18:31   ` Gregory Maxwell
2015-09-30 17:11     ` Mike Hearn
2015-09-30 17:58       ` Jorge Timón
2015-10-01 14:23         ` Tom Harding
2015-09-30 18:15       ` Adam Back
2015-09-30 19:26       ` Jeff Garzik
2015-09-30 19:56         ` Mike Hearn
2015-09-30 20:37           ` Jorge Timón
2015-09-30 21:06             ` Mike Hearn
2015-09-30 22:14               ` Jorge Timón
2015-10-01  0:11                 ` Jorge Timón
2015-09-30 22:17           ` Jeff Garzik
2015-09-30 23:25             ` Gregory Maxwell
2015-09-30 20:15       ` Gregory Maxwell
2015-09-30 21:01         ` Mike Hearn
2015-09-30 22:59           ` Gregory Maxwell
2015-10-01  4:08           ` [bitcoin-dev] Crossing the line? [Was: Re: Let's deploy BIP65 CHECKLOCKTIMEVERIFY!] Tao Effect
2015-10-01 16:39             ` Jeff Garzik
2015-10-01 20:17               ` Milly Bitcoin
2015-10-02 12:23               ` Mike Hearn
2015-10-02 13:14                 ` jl2012
2015-10-02 14:10                   ` Marcel Jamin
2015-10-02 16:37                 ` Gregory Maxwell
2015-10-07 15:00     ` [bitcoin-dev] Let's deploy BIP65 CHECKLOCKTIMEVERIFY! Anthony Towns
2015-10-07 15:46       ` Jonathan Toomim (Toomim Bros)
2015-10-07 16:02         ` Eric Lombrozo
2015-10-07 16:25           ` Eric Lombrozo
2015-10-07 16:26           ` Jonathan Toomim (Toomim Bros)
2015-10-07 16:38         ` Anthony Towns
2015-10-10  7:23       ` Anthony Towns
2015-10-12  7:02       ` digitsu
2015-10-12 16:33         ` Anthony Towns
2015-10-12 17:06         ` Anthony Towns
2015-10-13  0:08           ` digitsu
2015-09-29 20:03 ` Wladimir J. van der Laan
2015-09-30  4:05   ` Rusty Russell
2015-09-30  6:19     ` Adam Back
2015-09-30 12:30       ` Mike Hearn
2015-09-30 15:55         ` Jorge Timón
2015-09-30 19:17           ` John Winslow
2015-10-01  0:06             ` Rusty Russell
2015-09-30 17:14         ` Adam Back
2015-10-01  0:04       ` Rusty Russell
2015-10-02  1:57 NotMike Hearn
2015-10-02  2:12 ` GC
2015-10-05 10:59   ` Mike Hearn
2015-10-05 11:23     ` Jeff Garzik
2015-10-05 11:28       ` Mike Hearn
2015-10-05 12:04         ` Jorge Timón
2015-10-05 12:08           ` Clément Elbaz
2015-10-05 12:16             ` Jorge Timón
2015-10-05 12:29               ` Clément Elbaz
2015-10-05 15:42                 ` Jorge Timón
2015-10-05 12:10           ` Mike Hearn
2015-10-05 15:33             ` Jorge Timón
2015-10-05 16:46               ` Mike Hearn
2015-10-06  6:20                 ` Anthony Towns
2015-10-07  6:13                 ` Micha Bailey
2015-10-05 13:29   ` Jorge Timón
2015-10-05 13:24 ` Jorge Timón

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