Summary: A. Fiat and M. Naor [Crypto ’93, Lect. Notes Comput. Sci. 773, 480-491 (1994; Zbl 0870.94026)] presented a new encryption scheme designed for broadcast transmissions. The feature of this scheme is to allow a central broadcast site to broadcast secure transmissions to an arbitrary set of recipients. The authors model the problem of unconditionally secure broadcast encryption schemes with an information theoretic framework. They obtain tight limitations both on the number of private keys associated with each user and on the number of keys generated by the center. Finally the model is considered where interaction is allowed in the common key computation phase proving that the interaction cannot help in decreasing the size of the pieces of information given to the users in the broadcast encryption schemes. – No proofs are given. The complete version can be obtained from the authors.
For the entire collection see [Zbl 0847.00061].