Compared with other known functional encryption systems, this is the first system where the functionality is capable of recognizing an unbounded language. For example, in (Key-Policy) Attribute-Based Encryption (ABE) a private key SK is associated with a single boolean formula which operates over a fixed number of boolean variables from the ciphertext. In contrast, in our system a DFA M will meaningfully operate over an arbitrary length input w.
We propose a system that utilizes bilinear groups. Our solution is a "public index" system, where the message m is hidden, but the string w is not. We prove security in the selective model under a variant of the decision l-Bilinear Diffie-Hellman Exponent (BDHE) assumption that we call the decision l-Expanded BDHE problem.Category / Keywords: public-key cryptography / Functional Encryption Publication Info: Full version of CRYPTO 2012 paper Date: received 10 Jul 2012 Contact author: bwaters at cs utexas edu Available format(s): PDF | BibTeX Citation Version: 20120712:153141 (All versions of this report) Short URL: ia.cr/2012/384 Discussion forum: Show discussion | Start new discussion