[cap-talk] Firefox breaks the principle of identifiability

[Ben Laurie]

Jed Donnelley wrote:
> At 09:16 PM 2/7/2005, Ben Laurie wrote:
> 
>> Jed Donnelley wrote:
>>
>>> At 08:29 PM 2/7/2005, Ben Laurie wrote:
>>> ...
>>> For example, I gave the example where someone I trust could say, "If 
>>> you visit the site, view
>>> it's SSL certificate and find that it's MD5 Fingerprint is 
>>> A9:04:4D:...:E2:31:9A  then I can trust
>>> that it's "Paypal" the organization that you can place some trust in."
>>> Does that answer your question?...
>>
>>
>> I agree it solves the problem of confusable URLs. I can't get very 
>> excited about that without a solution to the problem of how I 
>> realistically get hold of things to associate petnames with. 
>> Currently, if I want to go to Paypal's site, I type it in - petnames 
>> don't help me.
>> ...
>> This would work. I don't believe it is practical.
> 
> 
> What don't you believe is practical?  The communication of the trust 
> relationship from one
> entity to another (e.g. from your existing bank to Paypal) or the 
> binding of the communicated
> trust to a Petname?  Or something else?

The physical communication of trust relationships.

> It seems to me that if I have an existing trust relationship and via 
> known secure communication
> with that trusted entity I receive a message like:
> _________________________________________________________________________
> You can trust the entity at www.paypal.com with the certificate with MD5 
> Fingerprint:
> 
> A9:04:4D:C2:74:5E:05:D9:28:44:E0:8C:53:E2:31:9A
> 
> to be the "Paypal" service as I describe in this document.  You may 
> assign it
> the Petname "Paypal" and trust it as described herein.
> __________________________________________________________________________
 >
> The one thing I think might be missing is the binding of the Petname to the
> fingerprint.  Binding it to an IP address or DNS name has known problems.
> If there was a binding to a fingerprint as above (I don't know, there 
> may be),
> would that suffice?  Would you consider that 'practical'?  If not, why not?

Let's say I start with actually visiting my bank, and getting the 
fingerprint of their cert. I then tediously type that into my machine. 
Now I can go to the bank's website, and find their trustable link to 
PayPal. So, I go to PayPal and transfer some money from my bank into my 
PayPal account. I want to buy something with that money, so I follow 
PayPal's trustable link to eBay. On eBay, I find Joe Sixpack selling the 
something, so I follow eBay's trustable link to Joe Sixpack. Joe Sixpack 
has a friend, Evil Bastard, and a trustable link to him on his website. 
Now I have a trustable link to Evil Bastard (who Joe Sixpack described 
as escrow.com) I give my money to Evil Bastard, who promptly disappears, 
as does Joe Sixpack.

How did this chain of trust help me?

Cheers,

Ben.