Cryptology ePrint Archive: Report 2004/212

ID-Based Encryption for Complex Hierarchies with Applications to Forward Security and Broadcast Encryption

Danfeng Yao and Nelly Fazio and Yevgeniy Dodis and Anna Lysyanskaya

Abstract: A forward-secure encryption scheme protects secret keys from exposure by evolving the keys with time. Forward security has several unique requirements in Hierarchical Identity-Based Encryption (HIBE) scheme: (1) users join dynamically; (2) encryption is joining-time-oblivious; (3) users evolve secret keys autonomously.

We present a scalable forward-secure HIBE scheme satisfying the above properties. Note that a naive combination of Gentry-Silverberg HIBE scheme with the forward-secure Public-Key Encryption scheme by Canetti, Halevi and Katz would not meet the requirements. We also show how our fs-HIBE scheme can be used to construct a forward-secure public-key Broadcast Encryption scheme, which protects the secrecy of prior transmissions in the Broadcast Encryption setting. We further generalize fs-HIBE into a collusion-resistant Multiple Hierarchical ID-Based Encryption scheme, which can be used for secure communications with entities having multiple roles in Role-Based Access Control. The security of our schemes is based on the Bilinear Diffie-Hellman assumption in the random oracle model.

Category / Keywords: public-key cryptography / Forward security, ID-Based Encryption, Broadcast Encryption

Publication Info: CCS 2004

Date: received 26 Aug 2004, last revised 30 Aug 2004

Contact author: dyao at cs brown edu

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Version: 20040830:120254 (All versions of this report)

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