The attribute of a person or enterprise that provides confidence to others of the qualifications, capabilities, and reliability of that entity to perform specific tasks and fulfill assigned responsibilities.
Source(s):
CNSSI 4009-2015
NIST SP 800-37 Rev. 2
NIST SP 800-39 under Trustworthiness from CNSSI 4009
NIST SP 800-53 Rev. 5 from CNSSI 4009-2015
NIST SP 800-53A Rev. 5 from CNSSI 4009-2015

  Computer hardware, software and procedures that— 1) are reasonably secure from intrusion and misuse; 2) provide a reasonable level of availability, reliability, and correct operation; 3) are reasonably suited to performing their intended functions; and 4) adhere to generally accepted security procedures.
Source(s):
NIST SP 800-12 Rev. 1 under Trustworthy System

  The degree to which the security behavior of a component is demonstrably compliant with its stated functionality.
Source(s):
NIST SP 800-160 Vol. 1 under trustworthy

  Worthy of being trusted to fulfill whatever critical requirements may be needed for a particular component, subsystem, system, network, application, mission, business function, enterprise, or other entity.
Source(s):
NIST SP 800-160 Vol. 2 Rev. 1 from NIST SP 800-160 Vol. 1

  Worthy of being trusted to fulfill whatever critical requirements may be needed for a particular component, subsystem, system, network, application, mission, enterprise, or other entity. Note: From a security perspective, a trustworthy system is a system that meets specific security requirements in addition to meeting other critical requirements.
Source(s):
NIST SP 800-160 Vol. 1 from Neumann04

  Worthy of being trusted to fulfill whatever critical requirements may be needed for a particular component, subsystem, system, network, application, mission, enterprise, or other entity. Note: From a security perspective, a trustworthy system is a system that meets specific security requirements in addition to meeting other critical requirements.
Source(s):
NIST SP 800-160 Vol. 1 from Neumann04

  The interdependent combination of attributes of a person, system, or enterprise that provides confidence to others of the qualifications, capabilities, and reliability of that entity to perform specific tasks and fulfill assigned responsibilities. The degree to which a system (including the technology components that are used to build the system) can be expected to preserve the confidentiality, integrity, and availability of the information being processed, stored, or transmitted by the system across the full range of threats.
Source(s):
NIST SP 800-161r1 from NIST SP 800-53 Rev. 5 - adapted

  Worthy of being trusted to fulfill whatever critical requirements may be needed for a particular component, subsystem, system, network, application, mission, enterprise, or other entity.  Note: From a privacy perspective, a trustworthy system is a system that meets specific privacy requirements in addition to meeting other critical requirements.
Source(s):
NISTIR 8062 under Trustworthiness from Neumann04 - adapted, NIST SP 800-160 Vol. 1

  Worthy of being trusted to fulfill whatever critical requirements may be needed for a particular component, subsystem, system, network, application, mission, enterprise, or other entity. Note From a privacy perspective, a trustworthy system is a system that meets specific privacy requirements in addition to meeting other critical requirements.
Source(s):
NISTIR 8062 under Trustworthiness from Neumann04 - Derived, NIST SP 800-160 Vol. 1

  Worthy of being trusted to fulfill whatever critical requirements may be needed.
Source(s):
NISTIR 8320A under Trustworthy