Recent Sentinel Enhancements

The current version of he Sentinel is based on the use of Removable Hard Disk Drives (RHDDs) installed in the PC 5-1/4" Bay to store up to 2 levels of restricted data. To date the RHDDs have been standard 2-1/4" electromechanical hard drives that require a spin up cycle to load the operating system and all software. The recent availability of high capacity solid state Flash Disk Drives that do not require a spin up cycle will provide a significant operational advantage for the Sentinel in the speed of changing security levels and in the number of security levels that can be supported. In addition, any modifications to the RHDDs or any computer storage media would have no impact on the EAL 4 Security Status of the Sentinel since the computer and all peripherals are outside the Sentinel Target of Evaluation. The current Sentinel patents also are not impacted since the storage media is not specified in the patents.

The Sentinel is based on periods processing in which changing security levels is based on deactivating one security level while simultaneously activating another level. Changing from one level to another entails activating the hard drive for the selected level along with any authorized USB I/O ports, Network Interface Devices (NIDS), and modems. It also requires deactivating the previous level also consisting of a hard drive and the authorized USB I/O ports, NIDs, and modem. The time duration to change levels is currently totally dependent on the spin up and spin down times of the electromechanical hard drives and can be as much as 30 seconds depending upon the drive and operating system being used. Since the I/O ports, NIDs, and Modem are solid state devices their transition times are negligible. With solid state Flash Drives the total security level transition time becomes negligible as well.

Another advantage of the solid state flash drives is their small size and low power requirements. This will allow many more hard drives to be supported than can currently be supported when the current electromechanical drives are used. The Sentinel could easily support 6-10 drives and their associated levels within the space that is currently allocated for a single RHDD using electromechanical drives. In addition the USB interface used with many flash drives could completely eliminate the need for the 5 ¼" drive Bay and allow the drives to be collocated within the existing Sentinel Security Module Assembly. The net result will be a less expensive Sentinel that could support many more Security Levels with a transition time between levels that is virtually instantaneous. This same approach could also be applied to the laptop version of the Sentinel. To make optimum use of the new Flash Memory technology the Sentinel is undergoing some physical modifications to the existing Security Module to integrate the new drives and implement any required USB port access.