Performance Evaluation of a Lightweight Threshold-Based Distributed Encryption Architecture for IoT Data Offloading

In mobile cloud computing (MCC), ensuring secure and energy-efficient data offloading remains a key challenge for constrained IoT devices. We propose a lightweight, threshold-based distributed encryption scheme combining CP-ABE with delegated symmetric encryption across multiple assisting edge servers. This architecture preserves data confidentiality and fine-grained access control while significantly reducing on-device computational overhead. We experimentally evaluate the proposed scheme using realistic parameters derived from a LoRaWAN-based sensor, considering Data-Owner-centric metrics including energy consumption, end-to-end encryption time, bandwidth overhead, throughput, and scalability. Results show energy savings exceeding 98% at the sensor side, at the cost of increased latency due to coordination and communication overhead. The proposed scheme enables scalable, fault-tolerant, and secure data sharing for IoT applications where real-time constraints are relaxed.