[ExI] Kevin Dowd on Bitcoin

Harvey Newstrom mail at harveynewstrom.com
Sat Jan 17 16:48:51 UTC 2015

Agreed, It's not the hashrate (speed or power) that allows this.  It is the conflict resolution protocol that allows this.

Whenever different reporting entities disagree on something, they vote.  Who mined a bitcoin first if multiple people claim it?  Who received a bitcoin first if multiple purchases were made with the same bitcoin?  Whose transactions do we accept and whose do we reverse when there are record disputes?  They vote.

Anybody with 51% voting rights can theoretically outvote the others any time they want.  Google for bitcoin 51%, majority, race attack, Finney attack, double-spending, history modification, selfish mining, time limits, and similar terms for more information.

Harvey Newstrom   www.HarveyNewstrom.com

> -----Original Message-----
> From: Bryan Bishop [mailto:kanzure at gmail.com]
> Sent: Saturday, January 17, 2015 10:11 AM
> To: ExI chat list; Harvey Newstrom; Bryan Bishop
> Subject: Re: [ExI] Kevin Dowd on Bitcoin
> On Fri, Jan 16, 2015 at 10:08 AM, Harvey Newstrom
> <mail at harveynewstrom.com <mailto:mail at harveynewstrom.com> > wrote:
> 	The protocol allows a large (over 51%) consortium to take any or all
> the bitcoins they want.
> That's not entirely true. Having lots of hashrate does not endow one with the
> ability to take or spend all existing BTC. The attacker can't prevent
> transactions from being created or relayed or sent, the attacker can't send
> coin that never belonged to the attacker, the attacker can't create coin out of
> thin air, etc. However, miners with lots of hashrate (say, more than 50%) can
> delay transactions from being included in blocks by not including any
> transactions in the blocks the attacker mines.
> - Bryan
> http://heybryan.org/
> 1 512 203 0507

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