[Security] About the Firefox 3 Security Dialog & others

Jonathan Schleifer js-xmpp-security at webkeks.org
Sat Aug 23 07:18:28 CDT 2008


Am 23.08.2008 um 11:04 schrieb Dirk Meyer:

> SAS does not work for me when I use bots. It also reduces it to one
> way removing the option of X.509 certificates which is something I
> need.

I never said SAS should be the only way, we need multiple ways. I  
suggest those:

* SAS with mnemonics
* Fingerprint verification
* CA, but no CA added in the client by default (so the user has to  
trust the CA manually, for example useful in a company so you don't  
have to verify every co-worker)

>> Having a 32-bit SAS encoded with Mnemonics (like already suggested
>> here) really sounds like a great idea.
>
> Why not encode a key fingerprint with Mnemonics? Looks like the same
> to the user.

Only taking 32 bit of the fingerprint and using Mnemonics is insecure  
as this is easy to forge - we already discussed it here.

BTW: It was argued a lot that ESessions misses a cryptanalysis, but if  
we are going to do extensions to TLS, we might need a cryptanalysis  
for this stuff too. TLS is useless if we add a verification method  
that is insecure.

--
Jonathan


--
Jonathan

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