Steps to reproduce:

Hello
Please add in this forum
Components for Chat Core (mozilla.org)
https://bugzilla.mozilla.org/describecomponents.cgi?product=Chat%20Core
the category:
POPTASTIC protocol for encrypted chat
to be able to discuss this open source and well-developed option to chat encrypted.

Actual results:

POPTASTIC is an open protocol for chat over email-server.
It is implemented in several applications and described in several books, latest e.g. at Theo Tenzer: Super Secreto - The Third Epoch of Cryptography: Multiple, exponential, quantum-secure and above all, simple and practical Encryption for Everyone, ISBN 978-3755761174.
Its origin at the encryption suite Spot-On has been further developed at e.g. the Spike Messenger App, Smoke Chat Messenger or the Delta Chat App.
The idea is simple: To chat with E-Mail over E-Mails-Servers but display the message in a chat style.
That is the one part and the other part of POPTASTIC is that the chat is encrypted between both partners.

Expected results:

Ideally here you use two GPG keys. That is the industry standard.
So, it should work, that you use your existing GPG key and import it into the POPTASTIC protocol handling chat app. Some Apps mentioned above use rust or python implementations of the encryption and cannot handle the standardized GPG key.?!
Second, GPG refers to RSA. RSA is obsolete since 2016.
That is why POPTASTIC should work using a McEliece Algorithm key too. That has been implemented in the open source Smoke Chat Messenger which can be found here:
https://f-droid.org/de/packages/org.purple.smoke/
(It uses also a referring Server called #SmokeStack (also found there and the app has one test server IP implemented)).
In this Messenger RSA and McEliece Algorithms are compatible, means, the RSA chat user can talk to the McEliece chat user. Please see the used library and implementation.
GPG / RSA and McEliece Keys of the chat should in Thunderbird be interoperable to be secure against quantum computers. Otherwise please use only the future proof McEliece Algorithm.
Some people might use also the term Chat over Imap (which is only the half part of the truth: The Post with ID 1743989 also can be added to the POPTASTIC protocol forum).
Thunderbird as an E-Mail Client has already every user equipped with an e-mail account and hence such a chat server is given.
This idea has been posted not to provide chat or the referring protocol or encryption, it is about using such a simple given server – as long e-mail-servers accept encrypted text over their servers (a second post will be made for the use of simple chat severs for chat in Thunderbird as an complimentary alternative to e-mail-servers as chat servers, that users can set up on their own easily).
The interest is to analyze the compatibility of RSA and McEliece shown in the Smoke Messenger and making it compatible with the implementations on Spot-On Messenger found here https://textbrowser.github.io/spot-on/ and the GPG Standard and the GPG specific implementation from e.g. above mentioned implementations.
Thanks for making the POPTASTIC Chat of (originally implemented in) Spot-On Encryption-Suite also available with McEliece Algorithm and compatibility with GPG in Thunderbird Chat.
That is the basis for all e-mails in Thunderbird being encrypted - and that is the future and has more importance than chat, hence the dedicated forum creation request for POPTASTIC encryption.
Thanks

POPTASTIC is an open protocol for chat over email-server.
It is implemented in several applications and described in several books, latest e.g. at Theo Tenzer: Super Secreto - The Third Epoch of Cryptography: Multiple, exponential, quantum-secure and above all, simple and practical Encryption for Everyone, ISBN 978-3755761174.

Unfortunately I don't agree about this being an open protocol -- being solely available in books doesn't sound like it was developed with input from multiple parties and without the protocol description being freely available it is difficult to implement.

Some people might use also the term Chat over Imap (which is only the half part of the truth: The Post with ID 1743989 also can be added to the POPTASTIC protocol forum).

It is unclear to me if there's any difference from the POPTASTIC protocol and Chat-over-IMAP then? If there isn't, then this is a duplicate of bug 1743989.

The POPTASTIC protocol has been implemented in the encryption chat and echo application spot-on, also in the GoldBug Messenger and has been described in then technical documentation of both software applications ten years ago, it has also been described in the book of Adams (2016), Edwards (2018), and Tenzer (2021). A Derivate has been implemented years after that in more than one mobile apps. Chat over Imap addresses only imap and POPTASTIC adresses Pop3 and Imap and is the originator of this protocol. POPTASTIC has also the McEliece encryption next to RSA while derivative apps have focused on GPG only. See the Spot-On Application for the implementation and technical description in the documents and code.

The POPTASTIC protocol has been implemented in the encryption chat and echo application spot-on, also in the GoldBug Messenger and has been described in then technical documentation of both software applications ten years ago

See the Spot-On Application for the implementation and technical description in the documents and code.

Please link to the protocol description(s). I'm not familiar with these projects. Ideally there's a single source which describes how these messengers can interoperate?

https://github.com/textbrowser/spot-on

https://github.com/textbrowser/spot-on/tree/master/branches/trunk/Documentation
https://github.com/textbrowser/spot-on/blob/master/branches/trunk/Documentation/Spot-On.pdf
https://github.com/textbrowser/spot-on/blob/master/branches/trunk/Documentation/Spot-On.odt

Poptastic ................................................................................................................................................... 39
Poptastic
Version 0.17 of Spot-On introduced Poptastic. The new mechanism allows participants to communicate via the IMAP, POP3, and SMTP protocols. Poptastic provides a medium for near real-time conversations as well as traditional e-mail.

See Code Ui:
https://github.com/textbrowser/spot-on/blob/master/branches/trunk/UI/spot-on-poptastic-retrophone-settings.ui

Code with keyword poptastic:
https://github.com/textbrowser/spot-on/blob/master/branches/trunk/Kernel/spot-on-kernel-b.cc

Manual
https://www.amazon.com/-/de/dp/3749435065

Magazine news
https://www.pro-linux.de/news/1/21822/poptastic-verschl%C3%BCsselter-chat-%C3%BCber-pop3.html

Screenshot Settings:
https://i.postimg.cc/ZYgddZYG/poptastic-settings.png

In the (Menu / tool / add participant) add Friend menu box you just add an e-Mail address and POPTATSIC adds the friend to encrypted chat friends list. Chat is made over email servers.

You can choose different encryption algorithms
https://i.postimg.cc/jdMd74hL/poptastic-key.png
RSA, McEliece etc. Some mobile Apps for POPTASTIC choose GPG, which is RSA.
RSA is not future proof. Implement McEliece.

This app makes RSA and McEliece Keys compatible and interoperable:
https://github.com/textbrowser/smoke

Ideally for TB find either a McEliece & RSA implementation (compatible chat with Spot-On) or an implementation based on GPG (Standard GPG keys) which are in a second step tried to be made compatible with RSA (as in the app above done with RSA & McEliece).

Echo-Testserver for Spot-On regular chat - then add email chat:
5.180.182.220: 4710

Users with RSA keys can chat with users with McEliece keys and vice versa:
Smoke Chat App with RSA and/or McEliece Keys - interoperability:
https://github.com/textbrowser/smoke/blob/master/Smoke/app/src/main/java/org/purple/smoke/Cryptography.java