Audio encoding
We don't send the audio recording: LPC compression calculates the coefficients for a filter the receiver uses with a carrier. Efficient and effective!
Steganography
Already used in Ancient Greece, we just hide the bytes inside a video stream. Taking advantage of a spread-spectrum like technique no one will ever notice changes in the video!
Overall system
The base system sets up a video conference, concealing the phone communication. Using a private key for the encoding, only server and client will know of the secret audio message!
