Reversible Data Hiding for Encrypted Audios by High Order Smoothness

This work presents a reversible data hiding method on encrypted audio files, where a data-hider, having no knowledge about the original content, tries to embed some additional data into the encrypted version of the content which was distributed from the content owner. A legal receiver, with the pre-negotiated decrypted key, can decrypt the encrypted content and get nearly the same version of the original medium. Moreover, if he/she has the pre-negotiated data-hiding key, the embedded data can be extracted, and therefore, the medium can be totally recovered. There are many kinds of media and some works targeting on hiding data into encrypted images have been proposed recently. Since human’s auditory system is more sensitive than human’s visual system, we apply a high order smoothness measurement to maintain the naturalness of a sound and let the content owner pre-calculate some necessary information for sound recovery, before encryption. With these two mechanisms, this work produces stego-audios of small quality degradation and has the capability to recover the original audios with zero error rate.