use iPHONE via SonoBus, as a remote MiC & SPEAKER(over iP) for a Pi4 encrypted audio conference CALL
Gstreamer provides the audio over ip with encryption via AES256 *plus an additional layer of security using 300Khz AM modulation/demodulation inside a virtual sound card operating at 768Khz sample rate
uses SDR MODULEs from RECRI KEYER to perform the modulation/demodulation https://github.com/recri/keyer
SONOBUS
https://sonobus.net/
IPhone uses the ios sonobus APP and a lighting to headset adapter
the iPHONE sends mic audio via sonobus, to a pi4 for modulation/encryption before being sent out to the other OP over a Gstreamer PIPELINE... the iphone receives via sonobus, the pi4's demodulated, decrypted gSTREAMER PIPELINE audio, from the other OP and is heard on the iphone headset/headphones via the adapter
NOTE: voice is bit too bassy on this video demo(forgot to turn off the bass boost...easily modified and eee-que'D for correction, but not done this time)