b. Insistence -- necessary information is perceived.

      c. Honesty -- users correctly interpret perceived information.

      d. Predictablility -- future states and system response time can be predicted from the current and prior observable states.
       

    5. Dialogue-based properties:
      a. Safety properties -- nothing bad ever happen in the system (e.g. a user password is never displayed as clear text ).

    b. Liveness properties -- something good will eventually happen ( e.g. the user will be able to log out of the system ).