关键词: 隐蔽通信, 区块链, 智能合约, 社交网络, Shamir秘密共享, 星际文件系统

Abstract: To address the problems of single-channel vulnerability, low transmission efficiency, and security risks when combined with the InterPlanetary File System (IPFS) in existing blockchain covert communication models, a blockchain and social network-based multi-channel covert communication model was proposed. First, the Content IDentifier (CID) returned after uploading secret files to IPFS was divided into multiple shares using the Shamir secret sharing algorithm. Then, an embedding algorithm based on Ethereum smart contracts and another based on zero-width characters in social networks were designed to achieve cross-channel collaborative transmission of shares. Next, a redundant share mechanism was introduced, so that the CID could still be reconstructed under unstable network conditions or partial share loss, and the share parameters could be dynamically adjusted to meet different security, latency, and cost requirements. Finally, the receiver was required to extract a sufficient number of shares reaching the recovery threshold from Ethereum and social networks to reconstruct the CID, thereby retrieving the secret information from IPFS. Experimental results show that under baseline parameters, the proposed model requires 21.02 seconds and only 1.01 USD to transmit 100 MB of data. Compared with existing models, the transmission efficiency was reduced from the minute level to the second level, and the cost was reduced by at least 40%. Superior security and robustness are demonstrated, making the model suitable for efficient, secure, and low-cost covert transmission of large-scale data.

Key words: covert communication, blockchain, smart contract, social network, Shamir secret sharing, InterPlanetary File System(IPFS)