Secret and Trustable Communication Channel over Blockchain Public Ledger

Blockchain public ledger is a trusted medium that provides incorruptible data storage and traceable transactions. However, due to its public verifiability, it is hard to compromise two functionalities at once, a covert channel and a verifiable communication medium. The existing methods are either vulnerable to statistical analysis or lack trustable delivery notifications due to off-chain message delivery. This paper fills the gap by proposing a Multi-addresses Random Set Encoding (MaRSE) to increase message covertness by retaining the natural transactions pattern and resisting statistical attacks. The method uses on-chain message delivery to preserve blockchain-based verification that provides a trustable communication medium for the communicating parties. As a result, our proposed method is robust to a brute force attack due to its unpredictable transaction sequence and high number possibility of addresses combinations. The proposed system has been implemented on Ethereum rinkeby networks with the stegano-transactions being recorded within block numbers 4932833 to 4932893.