A Covert Communication Method Combining Secret Sharing and Steganography

In the distributed environment, when all parties carry out the cooperative computing, there are problems of low scalability and privacy leakage. To solve the above problems, this paper proposes a scheme that integrates the secret sharing and distributed steganography. Arnold transform is performed to encrypt the secret before the communication, and this transform can effectively improve the robustness of secret transmission. After a secret is embedded in a cover, the scheme uses random numbers to generate multiple sub-stego-objects, then carries out the distributed storage and communication for these sub-stego-objects. The identity of the sender is verified by the receiver using Schnorr zero-knowledge proof at the local, which reduced interaction between the sender and the receiver, and no more information is not obtained by the receiver except the stego-object. As a result, the receiver does not communicate directly with the sender, which, to some extent, can avoid the attention of the steganography from external attackers. Additionally, this scheme can still work even in the case that some users were disconnected from the system after a stego-object is transmitted. After analyzing how the scheme supports more senders, the correctness of the scheme is also proved in detail.