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From: Tom <tomz@freedommail.ch>
To: bitcoin-dev@lists.linuxfoundation.org
Date: Fri, 23 Sep 2016 16:37:39 +0200
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Subject: Re: [bitcoin-dev] BIP draft: OP_CHECKBLOCKATHEIGHT
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On Friday 23 Sep 2016 09:57:01 Luke Dashjr via bitcoin-dev wrote:
> This BIP describes a new opcode (OP_CHECKBLOCKATHEIGHT) for the Bitcoin
> scripting system to address reissuing bitcoin transactions when the coins
> they spend have been conflicted/double-spent.
> 
> https://github.com/luke-jr/bips/blob/bip-cbah/bip-cbah.mediawiki


Can you walk us through a real live usecase which this solves?  I read it and 
I think I understand it, but I can't see the attack every giving the attacker 
any benefit (or the attacked losing anything).