Generic Transformation for Scalable Broadcast Encryption Schemes

Abstract

Broadcast encryption schemes allow a message sender to broadcast an encrypted data so that only legitimate receivers decrypt it. Because of the intrinsic nature of one-to-many communication in broadcasting, transmission length may be of major concern. Several broadcast encryption schemes with good transmission overhead have been proposed. But, these broadcast encryption schemes are not practical since they are greatly sacrificing performance of other efficiency parameters to achieve good performance in transmission length. In this paper we study a generic transformation method which transforms any broadcast encryption scheme to one suited to desired application environments while preserving security. Our transformation reduces computation overhead and/or user storage by slightly increasing transmission overhead of a given broadcast encryption scheme. We provide two transformed instances. The first instance is comparable to the results of the "stratified subset difference (SSD)" technique by Goodrich et al. and firstly achieves O(log n) storage, O(log n) computation, and O(log n log log n r) transmission, at the same time, where n is the number of users and r is the number of revoked users. The second instance outperforms the "one-way chain based broadcast encryption" of Jho et al., which is the best known scheme achieving less than r transmission length with reasonable communication and storage overhead.

A Novel Broadcast Encryption Scheme Based on SD Scheme Reconstruction

“…Broadcast center in private encryption based schemes can know or deduce every user's private key, and all the keys for one user has to be kept in secret memory. Most of the schemes [13] are in private encryption way. As to public encryption based schemes, the broadcast center doesn't need users' private key set, only the public keys can finish the ciphertext generation.…”

“…Their subset deduction procedure always can be seen as forming an interval from a line. The chain-based schemes include Skipping/Cascade/Combined chain (SCCC) scheme [12], HLL scheme [13], Log-key [14]scheme and so on.…”

Enabling private conversations on Twitter

“…Alternatively, we could use a one-to-many or many-to-many stateless broadcast encryption scheme [32,38,27,25], which ensures that re-keying is infrequent and that many possible subsets can be generated with little computational effort. At this point, we did not see any direct advantage of using such approaches over simply deriving the group key for a conversation from the content of the initial Direct Message in that conversation.…”

Public Key Broadcast Encryption Schemes With Shorter Transmissions

“…We note that a broadcaster possibly sends a message to a huge number of users; hence efficiency in transmission cost has been considered to be a critical measure by service providers. Since Fiat and Naor [1] first formalized broadcast encryption in the symmetric key setting, a large body of work [2]- [8] has been devoted to building efficient broadcast encryption schemes. Until now, the most efficient scheme in the symmetric key setting achieves transmission cost while maintaining user storage cost [4]- [8], where denotes the number of revoked users and denotes the total number of users.…”