Multiuser cryptographic techniques

ABSTRACT

This paper deals with new problems which arise in the application of cryptography to computer communication systems with large numbers of users. Foremost among these is the key distribution problem. We suggest two techniques for dealing with this problem. The first employs current technology and requires subversion of several separate key distribution nodes to compromise the system's security. Its disadvantage is a high overhead for single message connections. The second technique is still in the conceptual phase, but promises to eliminate completely the need for a secure key distribution channel, by making the sender's keying information public. It is also shown how such a public key cryptosystem would allow the development of an authentication system which generates an unforgeable, message dependent digital signature.

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