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Paper: Chosen Ciphertext Secure Broadcast Threshold Encryption (resp. Threshold-Traitor Tracing)

Authors:
Victor K. Wei
Fangguo Zhang
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URL: http://eprint.iacr.org/2006/282
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Abstract: Recently, Boneh, Gentry, and Waters '05 presented an efficient broadcast encryption, and Boneh, Sahai, and Waters '06 presented an efficient traitor tracing scheme. The former broadcast encryption result contains both a simpler chosen plaintext secure version and a more complicated but chosen ciphertext secure version. The latter traitor tracing scheme is only chosen plaintext secure. In this paper, we use the twin encryption technique of Naor and Yung '90 to add chosen ciphertext security to both papers. By``twinning", we extend the simpler chosen plaintext secure broadcast encryption to achieve chosen ciphertext security, and we extend the chosen plaintext secure traitor tracing to achieve chosen ciphertext security. We also extend both schemes to versions corresponding to threshold encryption which we call "broadcast threshold encryption" and "threshold-traitor tracing", i.e. tracing of threshold traitors. In these schemes, any $\theta$ un-revoked users can decrypt while $\theta-1$ users cannot. The tracing is to a set of $\theta$ users. We call this set a "threshold-traitor". Our broadcast threshold encryption is collusion resistant. Our threshold-traitor tracing is collusion resistant in its traceability.
BibTeX
@misc{eprint-2006-21774,
  title={Chosen Ciphertext Secure Broadcast Threshold Encryption (resp. Threshold-Traitor Tracing)},
  booktitle={IACR Eprint archive},
  keywords={cryptographic protocols / broadcast encryption, traitor tracing, threshold encryption, twin encryption},
  url={http://eprint.iacr.org/2006/282},
  note={ kwwei@ie.cuhk.edu.hk 13384 received 18 Aug 2006, withdrawn 24 Aug 2006},
  author={Victor K. Wei and Fangguo Zhang},
  year=2006
}