Covert Communication in Blockchain: A Survey
Zhentao Wei, Yingxue Liu, Yin Lei, Zhuo Chen, Xiangbo Yuan, Yihang Wei, Keke Gai · 2025
Blockchain covert channels have become a cutting-edge technique of information concealment that allows anonymous communication, censorship resistance, and privacy protection. The processes of blockchain-based covert communication are methodically examined in this survey, such as information embedding, transaction screening, and transaction obfuscation. In particular, this work analyzes temporal and storage covert channels in blockchain covert communication embedding mechanisms. To improve security and thwart discovery, transaction screening methods are also investigated, covering dynamic label creation, encryption-based screening, and fixed address screening. In order to enhance concealment, we have studied obfuscation strategies at several levels, including transaction fields, structures, and patterns. Blockchain covert communication has advanced, but there are still a few issues, which involve computational complexity, trade-offs between efficiency and secrecy, and a limited embedding capacity. This work offers a thorough analysis of blockchain covert channels and explores the means of adoptability and efficacy.