[messaging] Separation of concerns, usability, and partial verification

Jon Callas jon at callas.org
Thu Mar 20 17:57:57 PDT 2014

> I think in an ideal scenario, all my encrypted communication with Bob
> (me being Alice) would be linked.  Not the same _session_ but I meant
> in the sense of a continuation of key material.  Encryption was
> opportunistic in conversation #1 (meaning there was no authenticity),
> but in conversation #2, we use a secret from the first conversation.
> Authenticity is not linked to a person, but to the cryptographic
> identity of whoever I talked to in Conversation #1.
> For example (monospace required):
> Initial OTR Conversation --- PGP Conversation --- Unacknowledged OTR Message
>                                     \
>                                      ----------- PGP Email
>                                       \
>                                        --------- ZRTP Call ----------- OTR Chat
> In this scenario, I talk with Bob on chat. We save a little bit of
> that session, and I send Bob an email (or vice versa) which includes a
> continuation of that session, Bob replies. I then send Bob an OTR
> message which is a continuation of the PGP conversation - but Bob
> doesn't reply.  Concerned, I send him a PGP email that is a
> continuation of the prior PGP conversation (not the OTR Message).  Bob
> still doesn't reply.  Very concerned, I initiate a ZRTP Call, which
> Bob finally answers.  My next conversation with Bob (an OTR Chat) will
> now include a continuation of the ZRTP session.
> I admit this is wildly futuristic and would be quite difficult to
> specify or build.

I don't think so. It's something I'm building now, more or less. It's not OTR, but something similar.


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