OMEMO in Psi+ portable 1.4 seems to present two fingerprints to the other party

[Funfief]

I am using OMEMO on Psi+ portable 1.4 (psi-plus-portable-1.4.1231_win7_x86_64.7z), per guidance received in this post:

https://groups.google.com/forum/#!topic/psi-users/6F9ojC5DsSY

Many thanks to Boris again.

Here's a question though.

Psi+ seems to present two fingerprints to the other contact as follows.

 - Clicking 'Show own fingerprint' in the Toolbar icon for OMEMO enters into the chat window only one fingerprint consisting of 8 blocks of 8 characters.

 - The other contact (myself at another terminal using Gajim) however receives a request to 'trust' two fingerprints from the same JID, one of which is the same 8x8 as above (the other being unseen in my Psi+ client).

I am sure there was no mix-up (a 3rd client or contact interfering) because I am not using any of these clients or JID to communicate with anyone as yet.

Questions:

 - At the Gajim end, should I 'trust' only the 8x8 fingerprint from Psi+'s 'Show own fingerprint'? Or should I trust both of the fingerprints as presented to Gajim?

 - Any explanation why two fingerprints get presented? Thanks.

P.S.

For anybody else trying to use OMEMO on Psi+, the process involved:

 - choosing a server that supports OMEMO

 - clicking 'Options > Plugin' and checking the OMEMO item (didn't have to do any further configuration)

 - clicking 'Options > Toolbars' and making sure that, for the Chat toolbar, OMEMO is in the 'Current Actions' column and

 - In the chat window, using the Toolbar icon for OMEMO to 'enable' OMEMO and to 'trust' the other contact's fingerprint.

[Boris Pek]

Hi,

> I am using OMEMO on Psi+ portable 1.4 (psi-plus-portable-1.4.1231_win7_x86_64.7z), per guidance received in this post:
> https://groups.google.com/forum/#!topic/psi-users/6F9ojC5DsSY

Great!

Once you have configured chat and groupchat toolbars it is time to update Psi+ to version 1.4.1303 or newer. There were a number of improvements in OMEMO plugin during this month:
https://github.com/psi-im/plugins/blob/master/generic/omemoplugin/changelog.txt

If you use portable build in portable mode, then for moving profile just move "Psi+" subdirectory from program directory. In case of usage of system profile you do not need to do anything, just launch new version of program.

Have in mind that Psi and Psi+ settings are completely compatible, but are stored in different directories. "Psi" and "Psi+" accordingly. For both cases: portable mode and system's profile.

> Psi+ seems to present two fingerprints to the other contact as follows.

The number of fingerprints for your interlocutor depends on amount of "devices" (xmpp client in OMEMO terms) which (s)he use. One key per device.

>  - Clicking 'Show own fingerprint' in the Toolbar icon for OMEMO enters into the chat window only one fingerprint consisting of 8 blocks of 8 characters.

Yes, this is a fingerprint of key for your current device. You may see it in "Own Keys" tab in OMEMO plugin options dialog as well.

>  - The other contact (myself at another terminal using Gajim) however receives a request to 'trust' two fingerprints from the same JID, one of which is the same 8x8 as above (the other being unseen in my Psi+ client).

Each user on each device should set the trust for own devices which (s)he trust and his(her) contact's devices. Messages and carbon copies of messages will be sent only on trusted devices. Please read how OMEMO works!

> Questions:
>  - At the Gajim end, should I 'trust' only the 8x8 fingerprint from Psi+'s 'Show own fingerprint'? Or should I trust both of the fingerprints as presented to Gajim?

You may set trust to all devices which are currently under your control.

>  - Any explanation why two fingerprints get presented? Thanks.

See above.

> P.S.
>
> For anybody else trying to use OMEMO on Psi+, the process involved:
>  - choosing a server that supports OMEMO
>  - clicking 'Options > Plugin' and checking the OMEMO item (didn't have to do any further configuration)
>  - clicking 'Options > Toolbars' and making sure that, for the Chat toolbar, OMEMO is in the 'Current Actions' column and
>  - In the chat window, using the Toolbar icon for OMEMO to 'enable' OMEMO and to 'trust' the other contact's fingerprint.

You forgot one important step:
- Psi+ should be re-started after enabling of OMEMO plugin before its real usage.

Unfortunately some Psi plugins may not work as expected promptly after activation and restart is need...

--
Boris