Sprints/2020 March Duesseldorf
This Sprint is focussed on creating the next iteration of the OMEMO XEP.
- Come up with a (rough?) threat model
- What does OMEMO protect against?
- What are the limitations?
- What can an attacker, eg. the server, do to hinder encrypted communication?
- 12-byte IVs
- Restructure PEP usage to use one device node with multiple items (One item for each device); Maintain index node? (so we have something to +notify on)
- Describe usage of OMEMO in MUCs (MUST be non-anonymous, RECOMMENDED to be members-only, …)
- PEP access model SHOULD (or RECOMMENDED) to be open (explain security consequences of that.)
- Link device IDs to the JID in stanzas to avoid the struggles implied by possible ID clashes
- Specify user-defined labels for devices/OMEMO identities to simplify key management
- Maybe a different way to generate device IDs that is guaranteed to create non-clashing IDs
- Describe in more detail how devices get activated inactivated (message from a device, or PEP event, what ever comes last)
- Describe how to opt-out of OMEMO again.
- Ratchet Length Counter to determine stale devices. This includes automatic sending of empty messages (ping messages) to forward the ratchet.
- Describe optional server please give me one pre-key+idenity key and then remove the pre key protocol
- Shorter element names for elements that are often repeated
- Complete session by sending key transport message upon receiving a prekey message.
- Stop using protobuf and build XML instead? (problem: need unique serialization method)
- Describe behaviour of recovering from broken session.
- Clear up the one-time pre key thing
- The security and business rules of 0420 are confusing and don’t communicate the potential impacts very well. I think those need to be rewritten before start to implement it and potentially end up in dangerous situations.
- Do not silently discard any messages.
- Require servers to persist PEP nodes
PEP, custom PreKey upload and download protocol, labels, group chats, fix 'list' -> 'devices', create '<keys jid="foo">' wrapper, recovery from broken sessions.
- Tim & Andy:
Figure out what we need to redefine; and redefine it. OTPK behaviour cleanup.
- Paul: Mention threat model in Requirements (for example Trust Management is out of scope), SCE integration
- Klaus & Marvin:
active, inactive, staleness, opt-out
Since multiple people are going to work on multiple parts of the XEP simultaneously we probably need a git and commit early and often. Other and better ideas welcome.
Idea by Syndace: I'm hosting a ShareLaTeX instance, which allows you to collaboratively work on the same LaTeX document at the same time, including a history of changes etc. We could write the XEP there and later port it into the required XML structure. As an alternative I also host a HackMD instance, which is the same thing but for Markdown documents.
- Current OMEMO Specification
- Double Ratchet Specification
- Extended Triple Diffie Helmann Handshake (X3DH)
- XEdDSA Signature Scheme
Dates and Times
Saturday, March 7th - Sunday, March 8th 2020
Join us in the chatroom: xmpp:firstname.lastname@example.org?join
Also accessible via https://chat.cluxia.eu/anon/#xmpp-sprint
Wyndham Garden Düsseldorf City Centre Königsallee
|Name (optional)||Nickname||Sprint project(s)||booked||comments|
|Paul Schaub||vanitasvitae||Revolutionize E2EE||yes|
|Tim Henkes||Syndace||guess what!||yep|