Message-ID: <54CFE5D5.2070908@worcel.com>
Date: Tue, 03 Feb 2015 10:02:13 +1300
From: Pedro Worcel <pedro@worcel.com>
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To: bitcoin-development@lists.sourceforge.net
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Subject: Re: [Bitcoin-development] Proposal to address Bitcoin malware
Precedence: list

I think what he is saying is that there is no point in having three 
signatures if they are not segregated in a secure manner. This is to 
say, if you use your computer as one "factor", and a third party website 
as another, but you use the same computer to access the website, there 
is no gain in security.

Another example would be an android phone. If your computer is 
compromised and your browser is authenticated to your Google account, 
you could remotely install an "app" on your phone.

I don't know if I understood/explained myself correctly; I think two 
factor is better than one and there is a security gain if implemented 
securely.

Cheers!
Pedro

On 2/3/2015 8:58 AM, Brian Erdelyi wrote:
>> Confusing or not, the reliance on multiple signatures as offering greater security than single relies on the independence of multiple secrets. If the secrets cannot be shown to retain independence in the envisioned threat scenario (e.g. a user's compromised operating system) then the benefit reduces to making the exploit more difficult to write, which, once written, reduces to no benefit. Yet the user still suffers the reduced utility arising from greater complexity, while being led to believe in a false promise.
> Just trying to make sure I understand what you’re saying.  Are you eluding to that if two of the three private keys get compromised there is no gain in security?  Although the likelihood of this occurring is lower, it is possible.
>
> As more malware targets bitcoins I think the utility is evident.  Given how final Bitcoin transactions are, I think it’s worth trying to find methods to help verify those transactions (if a user deems it to be high-risk enough) before the transaction is completed.  The balance is trying to devise something that users do not find too burdensome.
>
> Brian Erdelyi
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