Hello!
I was just browsing FSF's High Priority Projects (https://directory.fsf.org/wiki/Collection:High_Priority_Projects) and PRISM (https://directory.fsf.org/wiki/Collection:PRISM).
I found out that most applications listed there for secure and private communications were not imported into Guix yet. The applications are:
[1] CyrptoCat (https://directory.fsf.org/wiki/Cryptocat)
[2] Ekiga (https://directory.fsf.org/wiki/Ekiga) *
[3] Empathy (https://directory.fsf.org/wiki/Empathy) *
[4] Jitsi (https://directory.fsf.org/wiki/Jitsi) **
[5] Linphone (https://directory.fsf.org/wiki/Linphone)
[6] Mumble (https://directory.fsf.org/wiki/Mumble)
[7] PyBitMessage (https://directory.fsf.org/wiki/PyBitmessage)
[8] Ricochet (https://directory.fsf.org/wiki/Ricochet)
[9] Twinkle (https://directory.fsf.org/wiki/Twinkle)
[10] Wire (https://directory.fsf.org/wiki/Wire) **
* Part of GNOME, but not in Guix yet.
** Very useful for non-techsavvy users.
Thank you!