High integrity

High integrity is a design principle and quality classification applied to software systems where failure could result in serious consequences such as loss of life, significant financial damage, environmental harm, or critical mission failure.

Synonyms include safety-critical, mission-critical, and life-critical systems. In the Apollo era, the term used was man-rated systems.

High integrity software must operate with levels of reliability, safety, and correctness far exceeding those expected of ordinary commercial software. [Reliability] and [availability] are first-class design concerns, requiring systematic attention throughout the entire development lifecycle, from requirements analysis through to deployment and maintenance.

Systems designed to a high integrity standard are characterized by rigorous development processes and the use of formal verification methods and extensive testing and validation regimes. Strict safety and security requirements are embedded in the specification, and there is comprehensive documentation and traceability between requirements and implementation.

In addition, regulatory [compliance] and certification against applicable standards are often mandatory for high integrity systems. Widely recognized certification frameworks include DO-178C (for aviation software), IEC 62304 (medical device software), and ISO 26262 (automotive safety systems).