General access structures in audio cryptography

We propose and analyze a new type of cryptographic scheme, which extends principles of secret sharing to Morse code-like audio signals. The proposed "audio cryptography scheme" (ACS) is perfectly secure and easy to implement. It relies on the human auditory system for decoding. "Audio sharing schemes" (ASS) proposed earlier were based on disguising secret binary message with a cover sound. Moreover, only 2-out-of-n audio sharing schemes have ever been proposed. Our scheme correlates strongly, and is analogous to schemes in well-studied visual cryptography. Consequently, we were able to use the existing visual cryptography constructions and obtain not only k-out-of-n audio sharing schemes, but also the most general audio cryptography schemes for qualified subsets. In audio cryptography scheme for qualified subsets, a subset of participants can recover the secret audio signal only if some qualified subset of participants is its subset