A Group Covert Communication Method of Digital Currency Based on Blockchain Technology

With the rapid development of the Internet, it has become a hot spot in protecting important information from illegal theft and destruction during network transmission. The characteristics of strong robustness, anonymity and distributed transmission in blockchain technology can precisely make up for the disadvantages faced by traditional covert communication in transmitting important data, such as poor robustness, easy exposure of participants and difficulty in achieving group covert transmission. Therefore, a group steganography method for digital currency based on blockchain technology is proposed in this paper. In this method, an index matrix of address interaction is designed for group covert communication, using the address interaction relationship and transaction amount to hide secret message alternately, the transaction hiding secret message is published on the blockchain. In different groups, the receivers use different keys to extract different secret message. The method proposed also introduces a fine-grained group division mechanism to control the spread of secret information and reduce the risk of secret information leakage. And the application scenarios of the method proposed are more universal, breaking the limitation of using a single digital currency for covert communication on the blockchain. In addition, the proposed method modulates the number of addresses reasonably by sensing the generation time of the block, enhancing the concealment of the method. Through practical tests on a variety of mainstream digital currencies, the experimental results show that digital currencies with smaller block generation times need to consume less embedding time.