Information-Theoretic Timed-Release Security: Key-Agreement, Encryption, and Authentication Codes

  • Yohei Watanabe
  • Takenobu Seito
  • Junji Shikata
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7412)


In this paper, we study timed-release cryptography with information-theoretic security. As fundamental cryptographic primitives with information-theoretic security, we can consider key-agreement, encryption, and authentication codes. Therefore, in this paper, we deal with information-theoretic timed-release security for all those primitives. Specifically, we propose models and formalizations of security for information-theoretic timed-release key-agreement, encryption, and authentication codes, and we present constructions of those ones. In particular, information-theoretic timed-release encryption and authentication codes can be constructed from information-theoretic timed-release key-agreement in a generic and simple way. Also, we derive tight lower bounds of sizes of secret-keys and show an optimal construction for information-theoretic timed-release key-agreement. Furthermore, we investigate a relationship of mechanisms between information-theoretic timed-release key-agreement and information-theoretic key-insulated key-agreement. It turns out that there exists a simple algorithm which converts the former into the latter, and vice versa. In the sense, we conclude that these two mechanisms are essentially close.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Yohei Watanabe
    • 1
  • Takenobu Seito
    • 1
  • Junji Shikata
    • 1
  1. 1.Graduate School of Environment and Information SciencesYokohama National UniversityJapan

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