Paper 2006/306

Revisiting the Security Model for Timed-Release Public-Key Encryption with Pre-Open Capability

Alexander W. Dent and Qiang Tang


In this paper we investigate a security model for Timed-Release Encryption schemes with Pre-Open Capability (TRE-PC schemes) proposed by Hwang, Yum, and Lee. Firstly, we show that the HYL model possesses a number of defects and fails to model some potentially practical security vulnerabilities faced by TRE-PC schemes. Secondly, we propose a new security model for TRE-PC schemes which models the securities against four kinds of attacker and avoids the defects of the HYL model. We also work out the complete relations among the security notions defined in the new model. Thirdly, we introduce the notion of TRE-PC-KEM, which is a special type of KEM, and show a way to construct a TRE-PC scheme using a TRE-PC-KEM and a DEM. Finally, we propose an instantiation of a TRE-PC-KEM and prove its security.

Available format(s)
Public-key cryptography
Publication info
Published elsewhere. Summary of results accepted for publication in ISC 2007
EncryptionTimed-release encryption
Contact author(s)
a dent @ rhul ac uk
2007-06-28: last of 2 revisions
2006-09-06: received
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Short URL
Creative Commons Attribution


      author = {Alexander W.  Dent and Qiang Tang},
      title = {Revisiting the Security Model for Timed-Release Public-Key Encryption with Pre-Open Capability},
      howpublished = {Cryptology ePrint Archive, Paper 2006/306},
      year = {2006},
      note = {\url{}},
      url = {}
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