[Cryptography] NSA security guidelines for videoconferencing

[Florian Weimer]

* Whitfield Diffie:

> Encryption can be end-to-end but for security to be end-to-end the key
> negotiation has also to be end-to-end.

I would rather say there have to be some key at each end that cannot
be negotiated.

As far as I can see, there is no way to have security in the strong
end-to-end sense with a service that offers any form of password
recovery (and repatriating the identity to another device in case the
original device is lost).  Basically, your identity in the system has
to be tied to the key material you generated, and if you lose access
to that, you'll need a new account.  It's possible to lessen the
impact of this event by keep billing separate, but it still does not
seem compatible with what people expect from such services.

It also does not seem the main problem that video conferencing
currently faces: ensuring that the right people have access to
meetings.  Not so much to protect confidentiality, but to avoid
disruptions.