Cryptology ePrint Archive: Report 2013/505
Improvement of One Anonymous Identity-Based Encryption
Zhengjun Cao and Lihua Liu
Abstract: In 2009, Seo et al. proposed an anonymous hierarchical identity-based
encryption (IBE). The ciphertext consists of $(C_1, C_2, C_3, C_4)$, where $C_1$ is the blinded message, $C_4$ is the blinded identity,
both $C_2$ and $C_3$ are used as decrypting helpers. To prove its security, the authors defined five games and introduced a strong simulator who is able to select different Setups for those games.
In this paper, we optimize the IBE scheme by removing one decrypting helper and the strong simulator. We show its security under the $\ell$-computational Diffie-Hellman assumption with a normal simulator who only requires a unique Setup.
Category / Keywords: cryptographic protocols / Anonymous identity-based encryption; bilinear groups of composite order; doubly randomized key; strong simulator.
Date: received 16 Aug 2013
Contact author: liulh at shmtu edu cn
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Version: 20130817:204559 (All versions of this report)
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