# Security by Design **Domain:** Cybersecurity / Systems Engineering **Doc Type:** Architectural Principle Node **Maturity:** Established **Related:** [[Cybersecurity]], [[Mental Privacy]], [[BCI Metadata]], [[Neural Data Sovereignty]] --- ## Definition **Security by design** integrates threat modeling, least privilege, secure defaults, compartmentalization, encryption, key management, authentication, authorization, logging, update strategy, recovery, and failure handling into a system's architecture from the beginning. ## Neural-interface relevance Neural systems create unusually sensitive attack surfaces because compromise may expose clinical identity, inferred mental state, actuator control, stimulation capability, or a longitudinal cognitive record. Security must cover devices, transport, storage, models, interfaces, operators, and supply chains.