Hitchhiker's Guide to Secure Checkpointing on Energy-Harvesting Systems

The rise of energy-harvesting techniques hastens battery independence for the world's most energy-efficient devices. However, the unpredictability and scarcity of harvested energy mandates intermittent computation. Intermittent computation enables correct forward progress of long-running applications by bridging short bouts of computation with checkpoints. Checkpoints save the intermediate application state to non-volatile memory so that it can be restored and resumed post power cycle. Intermediate state storage opens the door to data at rest attacks as attackers can read, modify, and replay checkpointed state to undermine system security. Secure checkpointing approaches address the threat of attacker-accessible intermediate program state. This paper surveys the stateof-the-art secure checkpointing techniques, creating a unified threat model, taxonomy and analysis of defenses, and threat-specific defense recommendations that build on the state-of-the-art. This survey serves as a guide for any energy harvesting systems researcher or developer to existing secure checkpointing techniques and highlights the need for future work.