Abstract: Techniques are disclosed to provide security for graphical user interface elements being displayed in a system having a host operating system and a high assurance operating system. Graphical user interface elements associated with the high-assurance operating system may be prevented from being obscured and from any partial transparency. Additionally, a piece of secret information may be stored and displayed by graphical user interface elements associated with the high-assurance operating system. Coordinating certain elements of the graphical user interface elements associated with the high assurance operating system also helps to identify legitimate elements associated with the high assurance operating system. Public title information may be furnished to a host operating system windowing system to identify a window owned by a process running on a high-assurance operating system. Private title information associated with the same window may be used in the high assurance operating system.

Abstract: Methods for maintaining the security of a secured execution environment on a system comprising said secured execution environment and a second execution environment are disclosed. A maintained current state for the secured execution environment is selected from among a group of possible states including a standard input mode state and a nexus input mode state. A flow of user input is directed according to the current state through a secure kernel of both the second environment and the secured execution environment.

Abstract: A security device watches over the secure functionality in a computer system. This “watcher” security device may be integrated within the computer system or may be separate from it. The security device queries the secure functionality to determine whether the state of the secure functionality is acceptable. If no satisfactory state exists, or if no response is received, then a signal is transmitted. The signal may be auditory (a buzzer) or visual (a flashing light) in order to signal to any user that the secure functionality has been compromised. Optionally, human input devices may be disabled, or a monitoring service notified, in conjunction with or in lieu of the signal. If the secure functionality includes a secret shared between the secure functionality and the user, then the security device may signal the secret. For example, where the secret is visual, the security device may display the secret.

Abstract: Methods for maintaining the security of a secured execution environment on a system comprising said secured execution environment and a second execution environment are disclosed. A maintained current state for the secured execution environment is selected from among a group of possible states including a standard input mode state and a nexus input mode state. A flow of user input is directed according to the current state through a secure kernel of both the second environment and the secured execution environment.

Abstract: Techniques are disclosed to provide security for user output and input in which a first, host operating system is used along with a second, high assurance operating system (nexus), where the first system provides at least some of the infrastructure for the second system. A trusted UI engine has a trusted input manager and a trusted output manager. The trusted input manager controls access to trusted input, distributing decrypted input to the host operating system where appropriate, or to the appropriate process running in the nexus. The trusted output manager manages output to the display, and allows trusted agents in the nexus to output data for display without needing to be aware of output-device-dependent details.

Abstract: Techniques are disclosed to provide security for user input in which a first, host operating system is used along with a second, high assurance operating system, where the first system provides at least some of the infrastructure for the second system. Two modes are presented. In a first mode, user data is passed to the host operating system. In a second mode, user data is retained in the second operating system for the use of the second operating system or processes running on the second operating system. Transitions between the nodes can be accomplished according to hypothecated user actions such as keystroke combinations, or when the user performs an action which indicates a programmatic activation of a process running in the second operating system.