Design documents are engineering records that explain how a device or system was planned, specified, and built. They can include schematics, component lists, interface specifications, manufacturing notes, and descriptions of design decisions. For hardware, these records help explain how circuits and components work together; for software and connected products, they may describe architecture, data flows, and dependencies.
In cyber security, design documents help engineers identify trust boundaries, sensitive components, and potential weaknesses before deployment. Defenders use them to review system architecture, verify that security controls match the design, and maintain or repair equipment reliably. Attackers may also study leaked or exposed documents to learn how a system is assembled and where it may be vulnerable. Protecting access to current, accurate records—and preserving their provenance—supports both secure engineering and later verification.