Subject: Re: [Bitcoin-development] alternate proposal opt-in miner takes double-spend (Re: replace-by-fee v0.10.0rc4)

From: Peter Todd <[email-masked]>
Date: Sun, 22 Feb 2015 14:07:11 +0000

On 22 February 2015 08:50:30 GMT-05:00, Matt Whitlock <[email-masked]> wrote:
>On Sunday, 22 February 2015, at 2:29 pm, Natanael wrote:
>> In other words, you are unprotected and potentially at greater risk
>if you
>> create a transaction depending on another zero-confirmation
>transaction.
>
>This happened to one of the merchants at the Bitcoin 2013 conference in
>San Jose. They sold some T-shirts and accepted zero-confirmation
>transactions. The transactions depended on other unconfirmed
>transactions, which never confirmed, so this merchant never got their
>money.

Great example! Systems that appear more secure than they really are to uninformed users are dangerous. Same reason why brain wallets are such scary technology, and equally, why I like to give a few dollars away every so often to the guys brute forcing weak ones.

>I keep telling people not to accept transactions with zero
>confirmations, but no one listens.

In my experience there's a pattern of "accept unconfirmed; get burned badly/see someone else get burned; stop relying on them" Although of course, there's some bias in that people contact me asking what to do after they get burned. :)