THE COMPUTER-NETWORK SECURITY PROBLEM IS SEEN TO BE NOT MERELY A COMMUNICATIONS PROBLEM, BUT RATHER A COMPLEX SET OF PROBLEMS DUE TO MULTISYSTEM NATURE OF THE NETWORK. OF THE ALTERNATIVE SECURITY MECHANISMS CONSIDERED, THE MOST VIABLE ARE CONSIDERED TO BE THE SECURITY CONTROLLER AND INTELLIGENT CRYTOPGRAPHIC DEVICE. THE CONCEPT EMPLOYING THE MECHANISMS INVOLVES THE USE OF A DEDICATED MINICOMPUTER TO CONTROL ACCESS TO A COMPUTER NETWORK THROUGH THE CONTROL OF DATA ENCRYPTION KEYS; I.E., PARAMETERS, TYPICALLY BINARY NUMBERS, THAT CONTROL THE PROCESSES OF ENCIPHERING AND DECIPHERING COMPUTER DATA. AN AUTHORIZED USER OR TERMINAL IN A COMPUTER NETWORK IS ISSUED AN ENCRYPTION KEY TO OBTAIN ACCESS AFTER THE CREDENTIALS OF THE USER OR TERMINAL HAVE BEEN VERIFIED. IN EXAMINING THE USE OF THIS SECURITY CONCEPT, THE NETWORK IS VIEWED AS CONSISTING OF SEVERAL LEVELS, AND THE PRESENTATION PROCEEDS IN A TOP-DOWN ANALYSIS INVOLVING THE FOLLOWING: (1) THE POLICY AND REQUIREMENTS ISSUES; (2) THE HOST COMPUTERS SECURITY CONTROL SYSTEMS; (3) THE INTELLIGENT CRYPTOGRAPHIC DEVICE; AND (4) THE COMMUNICATIONS NETWORK. WITHIN EACH LEVEL, THE ISSUES RELATED TO AUTHENTICATION, AUTHORIZATION, CONNECTION ESTABLISHMENT, CONNECTION USAGE, SECURITY MONITORING, AND SECURITY ASSURANCE ARE CONSIDERED. IN ADDITION TO TECHNICAL CONSIDERATIONS, PROCEDURAL AND ECONOMIC ASPECTS ARE DISCUSSED. IT IS BELIEVED THAT THE APPROACH SUGGESTED WILL PROVIDE THE NECESSARY CONTROL MECHANISMS TO HANDLE THE COMPLICATIONS OF THE NETWORK ENVIRONMENT AND PROVIDE A VIABLE AND EVOLUTIONARY APPROACH TO ACHIEVING THIS GOAL IN BOTH EXISTING AND FUTURE NETWORKS. A BIBLIOGRAPHY IS PROVIDED. (AUTHOR ABSTRACT MODIFIED--RCB)