Overview of Covert Channel Research in Blockchain Environment

Abstract

Covert channel is a method to hide information in public communication channels for covert transmission, aiming at ensuring data transmission security and making third parties unaware of the covert communication process. However, with the continuous progress of traffic analysis technology, traditional network covert channels can no longer guarantee their security. Blockchain, as an emerging technology that combines cryptography, consensus algorithms, and P2P networks, has characteristics such as decentralization, traceability, anonymity, immutability, and security, making it an ideal platform for constructing covert channels. This paper first introduces blockchain technology, elaborates on the development process of covert channels, researches and summarizes the existing classification methods of covert channels. Then it summarizes the general model of blockchain covert channel on the basis of traditional network covert channel and divides the process of constructing covert channel into two main stages: information transmission and information extraction. Next, starting from the six-layer architecture of blockchain, the blockchain covert channels are analyzed in depth and the blockchain covert channels are divided into six categories according to different levels and subdivided based on the structure and mechanism of each layer, which can help better understand the construction process of blockchain covert channels and explore potential covert channels. Finally, this paper discusses the limitations of blockchain technology for covert channels and proposes future research directions.

Keywords

• blockchain; covert channel; covert channel classification; information transmission; information extraction