Fully CCA2 secure identity-based broadcast encryption with black-box accountable authority

  • Authors:
  • Xingwen Zhao;Fangguo Zhang

  • Affiliations:
  • School of Information Science and Technology, Sun Yat-sen University, Guangzhou 510275, China and Guangdong Key Laboratory of Information Security Technology, Guangzhou 510275, China;School of Information Science and Technology, Sun Yat-sen University, Guangzhou 510275, China and Guangdong Key Laboratory of Information Security Technology, Guangzhou 510275, China

  • Venue:
  • Journal of Systems and Software
  • Year:
  • 2012

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Abstract

Abstract: The concept of accountable authority identity-based encryption was introduced as a convenient tool to reduce the amount of trust in authorities in identity-based encryption. In this model, if the Private Key Generator (PKG) maliciously re-distributes users' decryption keys, it runs the risk of being caught and prosecuted. Libert and Vergnaud proposed an accountable authority identity-based broadcast encryption, which allows white-box tracing or weak black-box tracing. Their scheme was proved only secure in selective-ID model. We present a weak black-box accountable authority identity-based broadcast encryption scheme, which is proven as fully CCA2 secure against adaptive adversary with tight reduction. Our scheme achieves O(m) public keys size, O(m) private keys size, and O(1) ciphertext length, where m is the maximum number of receivers allowed in each broadcast.