¹School of Computer & Information,Shanghai Second Polytechnic University, Shanghai, China
²School of Computer and Electronic Information, Guangxi University, Nanning, China

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Abstract—Recently Zhang et al. proposed a hierarchical identity-based encryption scheme which is the first efficient scheme where both ciphertexts and private keys achieve O(1)size, and is the best trade-off between private key size and ciphertext size at present. However, in this paper, it will be pointed out that their scheme exists an ambiguity or shortcoming which makes their scheme be insecure or non identity-based. Then, in order to overcome this problem, an improved hierarchical identity based encryption scheme is proposed with the same efficiency with Zhang et al.’s scheme (the private keys and ciphertexts of O(1)size). And, the security proof of the improved scheme also is given in the selective-identity model.

Index Terms—HIBE, selective-identity model, identity-based encryption, security analysis, constant size.

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Cite: Xiaoming Hu, Huajie Xu, Jian Wang, Yinchun Yang, Xiaolin Xu, "Short Hierarchical Identity-based Encryption in the Selective-ID Model," Journal of Software vol. 8, no. 7, pp. 1613-1619, 2013.