[OTR-dev] Problem during the Authenticated Key Exchange (AKE)

[Thomas Balthazar]

Hi,

* The situation :
I use libotr v4.0.0 in an iOS app I'm working on.
The objective-c wrapper I use is here :
https://github.com/tbalthazar/TBOTRManager

* My goal :
I try to have my app exchange messages with another app that uses OTR too (but not libotr).

* My problem
If the other app initiates the OTR conversation (sending a ?OTRv23? message), everything works fine.
When my app initiate the OTR conversation, I think I have a problem I don't understand in the AKE phase.

Here is the sequence of messages my app sends and receive :

- my app sends : ?OTRv23?
- my app receives : ?OTR:AAMC...

Here is the libotr callback sequence :

- update_context_list_cb
- create_instag_cb
- policy_cb
- update_context_list_cb
- max_message_size_cb
- inject_message_cb

The inject_message_cb asks to inject this message : ?OTR:AAMK...
Which I pass to otrl_message_sending, which returns the same ?OTR:AAMK message.

- my app sends : ?OTR:AAMK...
- my app receives : ?OTR:AAMR...

Here is the libotr callback sequence :

- policy_cb
- confirm_fingerprint_received_cb for username
- write_fingerprints_cb
- update_context_list_cb
- gone_secure_cb
- max_message_size_cb
- inject_message_cb

The inject_message_cb asks to inject this message : ?OTR:AAMS...
Which I pass to otrl_message_sending, which returns *another message* : ?OTR:AAMD...

- my app sends : ?OTR:AAMD...
- my app receives : ?OTR Error:

My understanding is that my app should have sent the ?OTR:AAMS message instead of ?OTR:AAMD.

I'm pretty new to this, I just learned about the AAMC/AAMK/AAMR/AAMS meaning in this message :
http://www.mail-archive.com/otr-dev@lists.cypherpunks.ca/msg00310.html

I'm a bit lost, especially since my app seems to work fine when the OTR conversation is initiated by the other party. I probably miss something obvious and would appreciate any help.

Please let me know if you have any tip regarding my problem.

Thanks a lot!
Thomas.