What does the principle of "fail securely" entail?

The principle of "fail securely" involves designing systems in such a way that they continue to uphold security measures even in the event of a failure. This means that if a system encounters a problem or malfunctions, it must remain resistant to unauthorized access or exploitation. For example, a system that fails securely would ensure that sensitive data remains protected and does not become inadvertently exposed to potential attackers when the system is operating improperly.

This principle is essential in maintaining the overall security posture of a system. It emphasizes the importance of designing software and systems that incorporate security considerations not just during normal operations, but also in adverse situations where failures might occur. User access to sensitive data should be strictly controlled, regardless of the state of the system, ensuring that failures do not inadvertently lead to breaches or leaks of sensitive information.