[anonsec] PAS issue 14 - leap of faith

[Joe Touch]

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Nicolas Williams wrote:
> On Mon, Mar 27, 2006 at 12:50:29PM -0800, Joe Touch wrote:
>> Nicolas Williams wrote:
>>> On Mon, Mar 27, 2006 at 10:35:44AM -0800, Joe Touch wrote:
>>>>> LoF isn't merely about accepting unauthenticated peers -- in the context
>>>>> of SSH, for example, it's about interactively asking if a peer's public
>>>>> key is "valid" and then recording it so that subsequently no such
>>>>> interaction is necessary.
>>>> This is the part I don't quite understand.
>>>>
>>>> Where's the LOF?
>>> It's what we as human users to do: "validate" (as if they even usually
>>> could, via some oob way) a peer's public key so that the application can
>>> create a pseudonymous-ID-(public key)-to-peer-address/ID/name/... binding.
>> That seems like a very specific thing - out-of-band validation. There's
>> no leap there - the user can (and seems like they're expected to)
>> validate the key out-of-band.
> 
> No, they usually can't, and even more commonly don't.  They take a
> "leap": "I'm not being attacked"; and usually this leap works out fine
> (which teaches them to keep this up).

The leap's at the user level, NOT at SSL. SSL thinks the user is
performing whatever validation - leap or not - the user wants.

Besides, they can:
	- check to see if the cert has the IP address they expect
	- check to see if the cert has the DNS name they expect
	- check the contents of the cert (some websites of unsigned keys
	this info for this purpose, under the assumption that an
	attack would need to spoof both the web server and the SSH
	server to work)

Joe
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