[OTR-dev] mpOTR protocol phases and research questions

[Greg Troxel]

Trevor Perrin <trevp at trevp.net> writes:

> Deniability is achieved because any party could forge records of
> communication with other parties that a 3rd-party judge could not,
> post-facto, cryptographically distinguish from actual records.
>
> Because such forgery is possible, "malleablility" of transcripts isn't
> necessary, and the OTR / mpOTR rigamarole around "modifiable
> transcripts" and publishing signing/MAC keys becomes unnecessary.  If
> you can *forge* transcripts from scratch, there's no need to modify
> existing ones.

It seems that the hard property is to simultaneously achieve:

  deniability

  authentication to the counterparty in real time

  confidentiality, which means more  than encryption, but also being
  sure that you are encrypting in a key that only the authorized
  counterparty has

It seems that OTR does all of this, and I don't understand how you
propose to get the second two properties with unsigned DH.

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