[Cryptography] Questions about crypto that lay people want to understand

[John Levine]

>That's marketing.  This is liability:
>
>NEITHER PARTY WILL BE LIABLE UNDER ANY CIRCUMSTANCES WHATSOEVER FOR ANY
>CONSEQUENTIAL, INDIRECT, SPECIAL, PUNITIVE, INCIDENTAL OR EXEMPLARY
>DAMAGES, INCLUDING WITHOUT LIMITATION LOST PROFITS OR REVENUES, WHETHER
>FORESEEABLE OR UNFORESEEABLE, EVEN IF SUCH PARTY HAS BEEN ADVISED OF
>THE POSSIBILITY OF SUCH DAMAGES.
>
>http://www.symantec.com/content/en/us/about/media/repository/ssl-subscriber-agreement.pdf

Right, that limits liability to actual damages, which is not the same
thing as no liability.  A part of the agreement you left out refers to
their "protection plan", which pays up to $1.5M in case of some admittedly
unlikely breaches on Symantec's part.

https://www.thawte.com/assets/documents/repository/agreements/extended-warranty-program.pdf

>It's hard to see, yes.  How about:  the CAs actively stop the browsers 
>from changing the security model to deal with any alternate model that 
>might prevent the spoofing, on the assumption that any better security 
>model won't sell as many certificates.

I'm intrigued.  What are these alternate models that Microsoft and
Google would implement if they weren't under the thumb of the industry
giants in the CAB forum?

>> The attack du jour is spear phishing a company's CFO or accounting
>> clerk to send fake mail appearing to be from the boss ...

>Which in theory is stopped by the security model - email that is signed 
>by the real boss looks different to the non-real boss.

The security model is that the clerk looks at her fripping mail, knows
that the real boss doesn't send mail from boss43542 at yahoo.com, and
calls the boss on the phone to verify odd requests.  Too many medium
and small businesses are run by people who imagine that this could
never happen to them and think that they're too busy and important to
use security protocols, even simple ones like code words that they're
supposed to put in any message authorizing a payment.  You could put
all the S/MIME keys you want into the MUAs and it wouldn't make any
difference.

R's,
John