The objective of this project is to formulate and validate a methodology for creating secure algorithms in cyber-physical systems. The algorithms must be secure even when the devices do not trust each other. A typical CPS is composed of many devices, each with both a cyber component and a physical component, interacting in a common physical system and communicating with their neighbors. The devices may be malicious and provide false information or fail to take actions as claimed, or the communication channel may be compromised.