Restricted use of IMP DDT

At the recent workshop on "Automated Resource Sharing on the ARPANET", considerable interest was expressed on the topic of network security. In particular, representatives of several sites felt that uncontrolled use of IMP DDT made access control mechanisms quite vulnerable to interception or tampering.* Individuals at the workshop seemed to be in general agreement that use of DDT should be much more controlled than at present. In addition, as the network continues to take on a more and more operational character, and NCC use of DDT (which must be coordinated with other DDT usage) increases** we begin to see other reasons for controlling access to the DDT mechanism.