OBJECTIVE: To develop a service that provides distributed, secure data storage and sharing on a tactical wireless ad hoc network. DESCRIPTION: The new generation of tactical radios and networks will include remote unmanned sensors and radio nodes that dynamically join and leave self forming networks and subnets. The dissemination and storage of data across wireless links pose new challenges on how these systems will access data and where the actual data will reside. The Joint Tactical Radio System Program (JTRS) encompasses a family of multi-functional Software Defined Radio (SDR) communications systems that provide the next generation of voice, video and data for the warfighter. Although JTRS is the platform of choice for this future, JTRS, and any tactical networking system, must be supported by developments in networking and applications to meet future warfighter data needs. Specifically, while distributed data storage and sharing is an important paradigm that has been embraced in many computing contexts, it faces unique challenges in the military wireless domain. Military tactical networks have unique characteristics that are not easily addressed by available commercial solutions existing today. Military networks are composed of mobile nodes with different, often highly-specialized mission functions and capabilities, such as, sensing, fusion, planning, command and control, situational awareness, storage, computation power, etc. Node mobility in a noisy, often-obstructed, adversarial communications environment causes nodes to lose contact with the network frequently and unpredictably. The network can, and often must, be partitioned into smaller sub-networks. Nodes can be lost due to loss of power or destruction, and they can be captured. Moreover, the data in the network is highly dynamic, time sensitive, and critically, it is prioritized relative to vital mission roles that vary by node and over time. Data must be reliably stored and accessed in military networks under the above conditions. Solutions for data storage and transmission in military mobile ad-hoc networks should address issues of i) performance: the warfighter should be able to access the information products needed for current mission functions efficiently and selectively; ii) security: the data stored and transmitted over the network should be secured from outside eavesdropping or loss of a node to destruction, capture, or compromise by an enemy; and iii) resilience: the data should be highly available in the face of node loss, interference and temporary loss of connectivity, with priority relative to mission roles and objectives. Proposed research developments should be compatible with planned future tactical platforms and components (e.g., JTRS), but are expected to impact other situations where highly-dynamic data is maintained in highly-disrupted networks. In the commercial world, first responder and homeland defense communication systems present similar characteristics and requirements. PHASE I: Develop initial concept design and model key elements of an enterprise level strategy to distribute and store digital data collected from nodes in a tactical mobile ad-hoc networking topology. Develop an initial concept design, identify and define key parameters necessary to store, secure and access data in a system where nodes dynamically join and leave the network in realistic, dynamic tactical scenarios. PHASE II: In Phase II the contractor will finalize and validate the"distributed data storage"design proposed in Phase I as well as construct and demonstrate a working prototype with a minimum of 30 networking nodes, showing resilience against lost nodes, network interference and protection of data-at-rest. The contractor will also provide a detailed plan for practical implementation in larger networks with potentially hundreds of nodes. PHASE III: The transition opportunities within the DoD will grow in parallel with the deployment and adoption of mobile ad hoc networks. A secure, distributed data, storage strategy will be necessary in order to share information between network nodes in a tactical environment. PRIVATE SECTOR COMMERCIAL POTENTIAL: Commercial systems are moving to a"cloud storage"topology and DoD systems will eventually make the same transition. Strategies developed through this SBIR will leverage existing research and develop a"distributed storage"strategy applicable for the first responder and homeland defense communication systems.