Efficient Signcryption with Key Privacy from Gap Diffie-Hellman Groups

  • Benoît Libert
  • Jean-Jacques Quisquater
Conference paper

DOI: 10.1007/978-3-540-24632-9_14

Part of the Lecture Notes in Computer Science book series (LNCS, volume 2947)
Cite this paper as:
Libert B., Quisquater JJ. (2004) Efficient Signcryption with Key Privacy from Gap Diffie-Hellman Groups. In: Bao F., Deng R., Zhou J. (eds) Public Key Cryptography – PKC 2004. PKC 2004. Lecture Notes in Computer Science, vol 2947. Springer, Berlin, Heidelberg


This paper proposes a new public key authenticated encryption (signcryption) scheme based on the Diffie-Hellman problem in Gap Diffie-Hellman groups. This scheme is built on the scheme proposed by Boneh, Lynn and Shacham in 2001 to produce short signatures. The idea is to introduce some randomness into this signature to increase its level of security in the random oracle model and to re-use that randomness to perform encryption. This results in a signcryption protocol that is more efficient than any combination of that signature with an El Gamal like encryption scheme. The new scheme is also shown to satisfy really strong security notions and its strong unforgeability is tightly related to the Diffie-Hellman assumption in Gap Diffie-Hellman groups.


signcryption Gap Diffie-Hellman groups provable security 

Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • Benoît Libert
    • 1
  • Jean-Jacques Quisquater
    • 1
  1. 1.UCL Crypto GroupLouvain-La-NeuveBelgium

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