Define the Concept of Trusted System?

A trusted system is a system that is relied upon to a specified extent to enforce a specified security policy. As such, a trusted system is one whose failure may break a specified security policy.

Trusted systems in the context of national or homeland security, law enforcement, or social control policy are systems in which some conditional prediction about the behavior of people or objects within the system has been determined prior to authorize access to system resources.

For example, trusted systems include the use of "security envelopes" in national security and counterterrorism applications, "trusted computing" initiatives in technical systems security, and the use of credit or identity scoring systems in financial and anti-fraud applications; in general, they include any system (i) in which probabilistic threat or risk analysisis used to assess "trust" for decision-making before authorizing access or for allocating resources against likely threats (including their use in the design of systems constraints to control behavior within the system), or (ii) in which deviation analysis or systems surveillance is used to ensure that behavior within systems complies with expected or authorized parameters.