Re: [Security] Gajim 0.12's E2E encryption UI

[Peter Saint-Andre]

Simon Josefsson wrote:

Brendan Taylor <[EMAIL PROTECTED]> writes:

I've posted a description (with screenshots) of Gajim 0.12's end-to-end
encryption UI: <http://necronomicorp.com/lab/gajim-0.12-esessions-ui>

I think it's generally a good model and would like to be able to do
something similar, whatever system we end up with.

That's useful, it looks like a fairly good user experience.

XMPP could use TLS and OpenPGP and achieve a similar user experience,
here's how:

Each client generate an OpenPGP key for the user when she creates an

account.

Or, presumably, a self-signed DSA or RSA key?

Instead of verifying a SAS in your example above, the users
needs to verify the OpenPGP fingerprint.  If a SHA-1 hash is too
techno-babbly, a human-readable transformation of the fingerprint could
be used.  Advanced users can configure the client to use their already
existing OpenPGP key if they want to re-use it for XMPP, which allows
for re-use of the existing web of trust.

Right, or re-use an existing X.509 cert (some organizations issue the latter to their employees) or obtain such a cert from a CA (e.g., the one we run at xmpp.net).

Advanced clients could notice when the remote's OpenPGP key is already
trusted via the web-of-trust, and then print both the OpenPGP
fingerprint and the names of all keys in the OpenPGP trust path.  This
allows users to have more confidence of the remote identity before
verifying the OpenPGP fingerprint herself.

Right.



- X.509 cert
- OpenPGP key
- DSA key
- RSA key



/psa

As far as I can see, we would treat all of the following in roughly the same way: Some of these might be more trusted than others (e.g., CA-issued cert, OpenPGP key that's in my WoT), but all of them can be used to show a fingerprint (or potentially SAS, or shared password a la SRP) to the user. The first interaction might involve a leap of faith (in the case of self-signed keys). Or if we can figure out a way to check fingerprints with other trusted entities on the network (e.g., people in my contact list), the leap of faith might be slightly less scary (e.g. this is what some people do now for ssh -- ask the server admin who creates your account what the fingerprint should be).

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