Cryptology ePrint Archive: Report 2007/313

Perfect Forward Secure Identity-Based Authenticated Key Agreement Protocol in the Escrow Mode

Shengbao Wang and Zhenfu Cao and Zhaohui Cheng and Kim-Kwang Raymond Choo

Abstract: There are several essential features in key agreement protocols such as key escrow (essential when confidentiality, audit trail and legal interception are required) and perfect forward secrecy (i.e., the security of a session key established between two or more entities is guaranteed even when the private keys of the entities are compromised). Majority of the existing escrowable identity-based key agreement protocols, however, only provide partial forward secrecy. Therefore, such protocols are unsuitable for real-word applications that require a stronger sense of forward secrecy --- perfect forward secrecy. In this paper, we propose an efficient perfect forward secure identity-based key agreement protocol in the escrow mode. We prove the security of our protocol in the random oracle model, assuming the intractability of the Gap Bilinear Diffie-Hellman (GBDH) problem. Security proofs are invaluable tools in assuring protocol implementers about the security properties of protocols. We note, however, that many existing security proofs of previously published identity-based protocols entail lengthy and complicated mathematical proofs. In this paper, our proof adopts a modular approach and, hence, simpler to follow.

Category / Keywords: cryptographic protocols / Authenticated key agreement; Perfect forward secrecy; Bilinear pairing; Provable security; Modular security proof

Publication Info: In submission

Date: received 12 Aug 2007, last revised 13 Aug 2007

Contact author: shengbaowang at gmail com

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

Version: 20070816:120811 (All versions of this report)

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