This document discusses modeling and optimizing the performance-security tradeoff in distributed networked control systems (D-NCS) using a coevolutionary genetic algorithm (CGA). It presents a tradeoff model for a system's dynamic performance and its security. The CGA is proposed as a paradigm to optimize this performance-security tradeoff for D-NCS. A Simulink-based testbed demonstrates the effectiveness of using the CGA to efficiently find optimal values in the performance-security tradeoff model for D-NCS.