A Prepositioned Secret Sharing Scheme for Message Authentication in Broadcast Networks

In modem electronic distribution networks, message authentication is an important objective of information security. This objective is met by providing the receiver of a message an assurance of the sender’s identity. As physical protection such as sealed envelopes is not possible for messages expressed as binary sequences, digital tools have been developed using cryptography. A major limitation of all cryptographic methods for message authentication lies in their use of algorithms with fixed symmetric or public keys. We describe a new key transport scheme, based on secret sharing, which not only allows each new message to be authenticated with a new key, but also generates different authentication keys for different groups of receivers in broadcast networks.