29 karma · joined October 29, 2016
See the source code on that:
- https://letsencrypt.pep.foundation/trac/browser/asn.1
- https://letsencrypt.pep.foundation/trac/browser/sync
As you say correctly, of course you've to take care: as a common denominator an id is used, in case of e-mail a certain mail address, whose e-mail channel for communicaion functions as the key exchange channel, too (meaning the devices send themselves messages ("beacons"), which are considered as technical messages by the p≡p engine and thus never shown to the user as such).
=> If you fear to have a cell phone hacked or lost, it's better to not put that in a device group. Also you can seperate business from private accounts or have different accounts and on top of that aliases for whatever purposes, referencing the same id (mail address). In short: you can have (like mostly today) no device group at all or just different device groups meeting your needs and "paranoia levels" (based on the trust you put in your devices).
The devices agree on a device group key pair, being the master key pair, still they sync all devices' private keys for that specific id, such that you can read all of your messages received on all of your devices (even if there were changing pubkeys in between used for encryption, because of your different devices, which were not yet synced in the past).
If a device is lost or stolen, that has to be manually signalized by one of the other devices in the device group and then the devices have to agree on an new device group key pair to encrypt their future communications (we're talking of PGP encryption here, so no forwad secrecy).
Cf. the documentation for screenshots how this looks (nowadays): https://prettyeasyprivacy.com/docs
That's kind of a TOFU (Trust On First Use) approach, but you can verify trust by comparing the fingerprints, in p≡p by default represented as dictionary words in your natural language (somewhat similar to Signal). That's suitable for comparison by phone (=> quickly done).
It provides an engine (written in C99) and adapters for the most important environments, in order to automatize key management and message transport.
It'll be the default way to automatically encrypt e-mails in Enigmail, where most OpenPGP traffic emerges from, anyways: https://twitter.com/pEpCouncil/status/791948659378106368
But that's just a start, as p≡p wants to transfer all text-based communications anyhow into the censorship-resistant, peer-to-peer GNUnet (using OTR or Axolotl crypto).
Cf. White Paper of p≡p: https://pep.foundation/docs/pEp-whitepaper.pdf
(Wikipedia article on p≡p showing its broad approach: https://en.wikipedia.org/wiki/Pretty_Easy_privacy)