July 1, 1994
      
                  
        
  Author(s)
  Robert H. Bagwill,   John  Barkley,   Lisa J. Carnahan,   Shu-jen H. Chang,   David R. Kuhn,   Paul  Markovitz,   Anastase  Nakassis,   Karen J. Olsen,   Michael L. Ransom,   John P. Wack
 
       
            
    
    
        The Public Switched Network (PSN) provides National Security and Emergency Preparedness (NS/EP) telecommunications. Service vendors, equipment manufacturers, and the federal government are concerned that vulnerabilities in the PSN could be exploited and