Definition ∞ A cross-chain covert channel is a hidden communication pathway between distinct blockchain networks. This channel permits the surreptitious transmission of information or control signals by exploiting subtle, often unintended, interactions or shared resources across different blockchains. Unlike overt cross-chain bridges designed for asset transfer, covert channels operate outside declared communication protocols, potentially for malicious purposes like data exfiltration or coordinated attacks. Detecting and mitigating these channels presents a complex challenge due to their subtle nature and reliance on unconventional data encoding methods.
Context ∞ The concept of cross-chain covert channels is a subject of academic research and advanced cybersecurity discussions within the blockchain space. News reports might discuss theoretical attack vectors or novel detection methods as interoperability solutions become more prevalent. The security implications for multi-chain ecosystems and the potential for stealthy data movement are key areas of concern.