audio encryption and decryption in matlab

Abstract

That can be achieved used some kind of public key cryptography (Public-key cryptography) were the recording device has a public-key which only works for encripting, and in the other side (the playback side) needs to have the private-key counterpart which can be used to decrypt.

A naive schema would be,

The idea is not to encrypt the whole audio using PKI, but using some kind of cryptographic envelop (2.2.4 What is a digital envelope?), where you generates a unique symmetric key for each recording used to encrypt (with AES (Advanced Encryption Standard process) or some other block cypher algorithm) the audio blob, but the public key of the recording device to protect the unique session/recording key.