Date Added: Mar 2012
The authors present a new Hierarchical Identity Based Encryption (HIBE) scheme with constant-size ciphertext that can be implemented using the most efficient bilinear pairings, namely, Type-3 pairings. Security argument is based on the dual-system technique of Waters. As a result, security can be proved under adaptive-identity attack and the security does not degrade with increase in the depth of the HIBE. The HIBE is obtained by extending an asymmetric pairing based IBE scheme due to Lewko and Waters. The extension follows an approach earlier used by Boneh, Boyen and Goh. The resulting HIBE is the only known scheme using Type-3 pairings achieving constant-size ciphertext and security against adaptive-identity attacks without random oracles.