Broadcast Encryption

Abstract

Abstract. We introduce new theoretical measures for the qualitative and quantitative assessment of encryption schemes designed for broadcast transmissions. The goal is to allow a central broadcast site to broadcast secure transmissions to an arbitrary set of recipients while minimizing key management related transmissions. We present several schemes that allow a center to broadcast a secret to any subset of privileged users out of a universe of size n so that coalitions of k users not in the privileged set cannot learn the secret. The most interesting scheme requires every user to store O( k log k log n) keys and the center to broadcast O(k2 log' k log n) messages regardless of the size of the privileged set. This scheme is resilient to any coalition of k users. We also present a scheme that is resilient with probability p against a random subset of k users. This scheme requires every user to store O(1og k log(l/p)) keys and the center to broadcast O(k log2 k log( l/p)) messages.

Graph-Decomposition-Based Frameworks for Subset-Cover Broadcast Encryption and Efficient Instantiations

“…Such a scheme is motivated largely by pay-TV systems, the distribution of copyrighted materials such as CD/DVD. Broadcast encryption schemes were first formalized by Fiat and Naor [13]. Since then, many variants of the basic problem were proposed.…”

Coding Constructions for Blacklisting Problems without Computational Assumptions

“…The two major works on blacklisting problems that have appeared in the literature have been the relatively early work of Fiat and Naor [13] and the more recent work of Wallner et. al.…”

“…Indeed, [27] uses a simple balanced binary tree based scheme. By using such a large number of decryption keys, both [13] and [27] are in fact able to achieve stronger properties, for example the scheme of [27] can allow the number of excluded users k to be arbitrary, rather than fixed in advance. To deal with this structural problem of needing so many decryption keys, for the special case of private-key based broadcast, [13], and to some extent work following [27] by Canetti et.…”

“…However, since the keys being used must come from some externally specified public key encryption scheme, pseudorandom keys need not suffice. Thus, applying the results of [13] or schemes descending from the scheme of [27] without computational assumptions would require an expo-nential number of public keys be stored for the purpose of maintaining public broadcast groups, whereas our results require only polynomially many public keys.…”

Multicast Group Authentication

“…This makes it necessary to deliver a decryption key to a potentially large number of receivers. Solutions for multicast key management and distribution such as GKMP [1] [2], SKMD [3], lOLUS [4], Broadcast Encryption [5] and SIM-KM [6] [7] have been proposed.…”