International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Identity-Based Threshold Decryption

Joonsang Baek
Yuliang Zheng
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Abstract: In this paper, we examine issues related to the construction of identity-based threshold decryption schemes and argue that it is important in practice to design an identity-based threshold decryption scheme in which a private key associated with an identity is shared. A major contribution of this paper is to construct the first identity-based threshold decryption scheme secure against chosen ciphertext attack. A formal proof of security of the scheme is provided in the random oracle model, assuming the Bilinear Diffie-Hellman problem is computationally hard. Another contribution of this paper is, by extending the proposed identity-based threshold decryption scheme, to construct a mediated identity-based encryption scheme secure against more powerful attacks than those considered previously.
  title={Identity-Based Threshold Decryption},
  booktitle={IACR Eprint archive},
  keywords={cryptographic protocols /},
  note={A short version of this paper is to appear in the proceedings of PKC 2004. 12410 received 10 Aug 2003, last revised 23 Dec 2003},
  author={Joonsang Baek and Yuliang Zheng},