CRYPTOGRAPHIC FILE STORAGE.

The significance of this paper is that it describes a cryptographic system that has been built. It is based on work by Gifford although it derives its architecture from DSS (Distributed Secure System). The architecture is LAN-based and comprises amongst other things a file server and a key server. The files are stored in 'post-box' fashion and integral use is made of public key encryption to govern read and write controls. Keys are categorised as either subject or object keys and are stored in key envelopes on the key server. Methods of controlling access to keys are based upon Gifford's sealing primitives. Keys are placed on a key server via a compilation process whose source is a specification of protection in a language called PROSP. The procedure is illustrated in an example and the file access procedure comprises a sequence of requests and replies between both servers, the special interface to the network and the workstation.