The US Naval Research Laboratory has developed a hybrid security architecture that introduces Multi-Level Secure (MLS) technology into environments consisting of Multiple Security Levels (MSL), and applied this schema as the basis for two Multi-Level information sharing systems. These systems are known as, Multilevel Chat (MLChat) and Multilevel Web (MLWeb).


The MLChat system provides a dynamic, near-real-time chat capability for users operating on multiple networks with differing security policies. A single MLChat server can support hundreds of users operating on two to fifteen network levels. It is well suited for the war fighter because it is quiet, works well in low bandwidth environments, is easy to use and allows multiple users to converse simultaneously. Furthermore, the system fits into existing architectures and requires no changes to networks or user workstations. MLChat has been certified and is listed on the Unified Cross Domain baseline list as a multilevel solution.

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The MLWeb system provides users, operating on multiple disparate networks, the ability to share data objects quickly, securely, and cost-effectively, in a manner that complies with DOD policies. Today, multiple instances of web repositories are maintained in each security domain. Data flowing among these domains is replicated using guards and air gaps. The MLWeb hybrid architecture provides a central data store within the multi-level system and allows access to information based on discretionary and mandatory security controls. The ML Web server eliminates cross-domain content synchronization problems, reduces administrative burdens, and reduces the cost of supporting multiple networks.

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