GitHub - converspace/otxt: Moved to https://github.com/otxt/otxt-s2s-protocol

3 min read Original article ↗

otxt (WORK IN PROGRESS)

HTTP-based distributed P2P short message communication protocol (to replace SMS).

Key ideas

  • Focus on Dark Social (SMS, Email, Whatsapp, Pair)
  • Private one-to-one short text messaging like SMS.
  • Messages limited to 256 characters. No new lines allowed.
  • Users identified by URLs intead of mobile numbers.
  • Not IM
    • No presense
    • But requires pairing before sending a msg
      • makes the protocol less chatty because of the shared secret instead of verifying authenticity of individual msgs
      • requiring manual approval helps with SPAM
  • Support in-reply-to for better conversations.
  • Security via HTTPS.

Alice pairs with Bob

Alice's otxt host discovers Bob's HTTPS otxt endpoint.

HEAD / HTTP/1.1
Host: bob.host
HTTP/1.1 200 OK
Link: <https://bob.host/otxt-endpoint>; rel="http://otxt.org/"

<html>
...
<link href="https://bobs.host/otxt-endpoint" rel="http://otxt.org/" />
...

Alice's otxt host sends pairing request to Bob's otxt endpoint

POST /otxt-endpoint HTTP/1.1
Host: bob.host
Content-Type: application/x-www-url-form-encoded

from=alice.host
to=bob.host
action=pair
secret=
id=tag:alice@example.com,2012-12-02:alice.host:pair:2
intro=<256_chars_introduction>

Bob could setup his otxt host to require manual or automatic approval.

Bob discovers Alice's HTTPS otxt endpoint

HEAD / HTTP/1.1
Host: alice.host
HTTP/1.1 200 OK
Link: <https://alice.host/otxt-endpoint>; rel="http://otxt.org/"

<html>
...
<link href="https://alice.host/otxt-endpoint" rel="http://otxt.org/" />
...

Bob's otxt host verifies Alice's add request

POST /otxt-endpoint HTTP/1.1
Host: alice.host
Content-Type: application/x-www-url-form-encoded

from=bob.host
to=alice.host
action=verify
id=tag:alice@example.com,2012-12-02:alice.host:pair:2
hash=<hash_of_from+id_using_alices_secret>

Now Bob and Alice can send each other messages using the shared secret that Alice orginally sent to Bob.

Alice sends a message to Bob

POST /otxt-endpoint HTTP/1.1
Host: bob.host
Content-Type: application/x-www-url-form-encoded

action=send
id=tag:alice@example.com,2012-12-02:alice.host:txt:2
from=alice.host
to=bob.host
txt=<256_chars_msg>
in_reply_to=tag:bob@example.net,2012-12-01:bob.host:txt:22
datetime=<datetime>
hash=<hash_of_..._using_shared_secret>

TODO

  • Use microformats instead of link header/element?
    • Almost always you will put it up on your page for "humans" so why not just use that!
    • <div id="me"><a href="https://example.com" rel="http://otxt.org/">https://example.com</a></div>
  • Discovery over http is not secure. Should that be made over HTTPS as well?
  • group messaging?
    • This is currently not possible because you need to add a contact before you can talk to them and not everyone in the group (comma separated to param) would have added everyone.
    • One way to do this is to treat a group just like any other person.
      • When a user creates a group, the group pairs with all members of the group.
      • When someone sends a msg to the group, the group forwards the msg to the members.
    • Alternatively, a new action relay can be introduced so that msgs from people that haven't paired can be sent via paired ones.
  • fetch profile? (maybe just use microformats to pick up public info and use this only for private info?)
    • GET /otxt-endpoint?profile=(all|email|name|avatar)&of=<>&from=<>&hash=<>
    • Allowed only after pairing since this will require the shared secret.
  • Multi-Media (using additional params)
    • img=<image_url>
    • vid=<video_url>
    • aud=<audio_url>
  • Links are first class citizens (Might have to skip this to enforce the 256 char limit?).
    • compose: This is how you [link](http://example.com)
    • display: This is how you <a href="http://example.com">link</a>
    • characters counted: This is how you link

See Also