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Paper: Chosen ciphertext secure public key encryption under DDH assumption with short ciphertext

Authors:
Xianhui Lu
Xuejia Lai
Dake He
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URL: http://eprint.iacr.org/2008/330
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Abstract: An efficient variant of the ElGamal public key encryption scheme is proposed which is provably secure against adaptive chosen ciphertext attacks(IND-CCA2) under the decisional Diffie-Hellman(DDH) assumption. Compared to the previously most efficient scheme under DDH assumption by Kurosawa and Desmedt [Crypto 2004] it has one group element shorter ciphertexts, 50\% shorter secret keys, 25\% shorter public keys and it is 28.6\% more efficient in terms of encryption speed, 33.3\% more efficient in terms of decryption speed. A new security proof logic is used, which shows directly that the decryption oracle will not help the adversary in the IND-CCA2 game. Compared to the previous security proof, the decryption simulation is not needed in the new logic. This makes the security proof simple and easy to understand.
BibTeX
@misc{eprint-2008-18007,
  title={Chosen ciphertext secure public key encryption under DDH assumption with short ciphertext},
  booktitle={IACR Eprint archive},
  keywords={public key encryption, IND-CCA2, DDH},
  url={http://eprint.iacr.org/2008/330},
  note={ luxianhui@gmail.com 14095 received 31 Jul 2008, last revised 3 Aug 2008},
  author={Xianhui Lu and Xuejia Lai and Dake He},
  year=2008
}