Cryptology ePrint Archive: Report 2006/085

Anonymous Hierarchical Identity-Based Encryption (Without Random Oracles)

Xavier Boyen and Brent Waters

Abstract: We present an identity-based cryptosystem that features fully anonymous ciphertexts and hierarchical key delegation. We give a proof of security in the standard model, based on the mild Decision Linear complexity assumption in bilinear groups. The system is efficient and practical, with small ciphertexts of size linear in the depth of the hierarchy. Applications include search on encrypted data, fully private communication, etc.

Our results resolve two open problems pertaining to anonymous identity-based encryption, our scheme being the first to offer provable anonymity in the standard model, in addition to being the first to realize fully anonymous HIBE at all levels in the hierarchy.

Category / Keywords: public-key cryptography / Linear assumption, bilinear maps, standard model

Date: received 3 Mar 2006, last revised 8 Jun 2006

Contact author: xb at boyen org

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Version: 20060608:225710 (All versions of this report)

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