Covert Communication-Assisted Computation Offloading Schemes in Blockchain-Enabled IoT*

Blockchain-enabled Internet of Things (IoT) can ensure security and trust in distributed environments through consensus mechanisms, becoming important application scenarios for secure computation offloading of smart devices. In the IoT, smart devices usually upload complex computing tasks to the base station (BS), and then obtain corresponding mobile edge computing (MEC) servers to perform computing tasks. However, considering the broadcast characteristics of wireless links and the limited resources of smart devices, task upload links with weak security protection are easy to be monitored by adversaries. Since traditional information encryption technology and physical layer security (PLS) technology focus on protecting information content, the existence of upload links is difficult to be protected, which may attract potential adversaries to launch serious attacks after discovering links. Due to the fact that physical layer covert communications aim to complete information transmission without being discovered by adversaries, we propose covert communication-assisted computation offloading schemes in blockchain-enabled IoT for smart devices. The energy consumption of the computation offload schemes is optimized while ensuring the covertness of the task upload link, the matching satisfaction of sensors and MEC servers. Numerical results show that the proposed schemes can obtain the maximum effective covert rate while reducing the energy consumption of computation offloading.