Is it possible to intercept voice data during call?

Question

I plan to develop Android application which will encrypt/decrypt voice data such that parties can communicate using secure channel. So the question is: how to intercept voice/au

Answer 1

I know there are apps that act like voice changer where they change your voice and transmit that thru gsm voice. Maybe you can make an app that takes the voice then modulate it to something like phase shift keying or digital radio monodiale like what hams used in vhf and hf radio communication and transmit the audio to gsm then demodulate it back to voice but instead of straight forward modulation demodulation you can add pgp, aes, or whatever encryption you like. I'm also intrested to see a project like this.

I think it would also be great if you could use this to transmit data thru voice gsm channel like the 56k modems in the past instead of the gprs channel.

See reference http://freedv.org/tiki-index.php http://www.aprs.org