Covert communication via blockchain: Hiding patterns and communication patterns

Blockchain technology has demonstrated promising potential for covert communication. Although a series of studies have investigated blockchain-based covert communication, systematic research on the information-hiding patterns and covert communication patterns built on the blockchain is absent. This paper aims to conduct a comprehensive analysis of the related patterns. Based on intensive investigation, we abstract and propose a reference model for blockchain-based covert communication. We accordingly identify five types of covert communication patterns, each with different roles for covert senders and covert receivers, which enable one-to-one and one-to-many communication. Using Bitcoin as an example, we analyze the data distribution of covert channels within the block and transaction structure. Furthermore, we compare the hiding patterns and covert communication patterns and discuss the challenges and promising directions to achieve secure, robust, and cost-effective covert communication using blockchain. This work can provide valuable insights into the potential of blockchain technology for covert communication and lay the foundation for future research in this area. •We find seven types of hiding patterns with covert channels in blockchain.•We discover five covert communication patterns on blockchain for real-world scenarios.•We infer features of covert channels in Bitcoin and recommend hiding capacity for these channels.