Secured Distributed Computing in Satellite
                 Communications Network Planning

       Z. George Mou, John Piorkowski, James Mayfield, Lien Duong
           Applied Physics Laboratory, Johns Hopkins University
                 george.mou@jhuapl.edu


This abstract reports the results of a two year R&D effort that
examined the application of secured distributed computing for
satellite communication network planning conducted at the the Applied
Physics Laboratory of Johns Hopkins University. 

Current military satellite communication network planning system rely
on obsolescent computing technologies, and are personnel-intensive,
complex, and unresponsive to user needs. In the future, the warfighter
needs the ability to expeditiously request and be assured access to
satellite communications resources. This requires him to dynamically
formulate communications service requirements in the field and interact
with a remote automated management system. There is a need to
determine whether advanced computing technologies could support the
airfighter requirement for timely access to satellite communications
resources. Secure distributed object technology, if applied properly,
would increase the likelihood of future satellite communication
network planning systems meeting the goals of the warfighter.

The architecture consists of applications and a database located with
a central planner, and only a client applications located with a lower echelon
planner. This architecture allows the lower echelon planner 
to define communication plans and determine supportability of those
plans based on data located in the central database. The interaction
between applications follows the distributed object model using OMG's
CORBA technology.

A prototype of the system has been implemented using Java and CORBA.
Since no implementation of the standard CORBA security service was
available at the time of the project, we implemented the security
features of the system using DSA.  A request for a satellite
communication resource is represented as a complex object in the
client application when the request is issued, the object is
serialized, encrypted and signed with digital signature with public
key based on DSA.  The CORBA interface between the requester and the
remote management system transmits the data as a sequence of CORBA
octets. The acceptance or rejection of the request is sent back with
the same security procedures using  CORBA callback. This design
therefore supports confidentiality, integrity, and authentication.

The prototype of the system was successfully completed and tested. It
demonstrated that secured distributed object model is a viable
technology that can be applied to  new generation of satellite
communication planning systems to enhance both functionality and
security.