Internet of Things (IoT) is a recent technology of connecting and communicating people, process, devices, and data; and it is expected to facilitate future communication and to increase quality of lives. Due to a very wide range of application areas, this technology needs some requirements such as sensing the targets in the network field, minimizing energy consumption, connecting with other IoT devices securely. For these reasons, many constraints need to be taken into account when deploying devices into the field. In this study, a multi-objective evolutionary algorithm based on decomposition (MOEA/D) is proposed to relocate to IoT devices randomly distributed in a certain area to optimize the efficient and secure coverage problem. Simulation results are evaluated by comparing MOEA/D with another well-known algorithm called non-dominated sorting algorithm II (NSGA-II). According to the results, there is a trade-off between the number of covered targets and the secure connection between devices. Also, MOEA/D achieves higher coverage ratio (higher number of covered targets), while NSGA-II provides higher number of secure connections.