Identity-based encryption gone wild
Ref: Michel Abdalla, Dario Catalano, Alexander W. Dent, John Malone-Lee, Gregory Neven and Nigel Smart. In M. Bugliesi, B. Preneel, V. Sassone, and I. Wegener, editors, 33rd International Colloquium on Automata, Languages and Programming - ICALP 2006, volume 4052 of Lecture Notes in Computer Science, pages 300-311. Springer-Verlag, 2006.
Abstract: In this paper we introduce a new primitive called identity-based encryption with wildcards, or WIBE for short. It allows to encrypt messages to a whole range of users simultaneously whose identities match a certain pattern. This pattern is defined through a sequence of fixed strings and wildcards, where any string can take the place of a wildcard in a matching identity. Our primitive can be applied to provide an intuitive way to send encrypted email to groups of users in a corporate hierarchy. We propose a full security notion and give efficient implementations meeting this notion under different pairing-related assumptions, both in the random oracle model and in the standard model.