Identity-Based (Lossy) Trapdoor Functions and Applications

  • Mihir Bellare
  • Eike Kiltz
  • Chris Peikert
  • Brent Waters
Conference paper

DOI: 10.1007/978-3-642-29011-4_15

Part of the Lecture Notes in Computer Science book series (LNCS, volume 7237)
Cite this paper as:
Bellare M., Kiltz E., Peikert C., Waters B. (2012) Identity-Based (Lossy) Trapdoor Functions and Applications. In: Pointcheval D., Johansson T. (eds) Advances in Cryptology – EUROCRYPT 2012. EUROCRYPT 2012. Lecture Notes in Computer Science, vol 7237. Springer, Berlin, Heidelberg


We provide the first constructions of identity-based (injective) trapdoor functions. Furthermore, they are lossy. Constructions are given both with pairings (DLIN) and lattices (LWE). Our lossy identitybased trapdoor functions provide an automatic way to realize, in the identity-based setting, many functionalities previously known only in the public-key setting. In particular we obtain the first deterministic and efficiently searchable IBE schemes and the first hedged IBE schemes, which achieve best possible security in the face of bad randomness. Underlying our constructs is a new definition, namely partial lossiness, that may be of broader interest.

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Copyright information

© International Association for Cryptologic Research 2012

Authors and Affiliations

  • Mihir Bellare
    • 1
  • Eike Kiltz
    • 2
  • Chris Peikert
    • 3
  • Brent Waters
    • 4
  1. 1.Department of Computer Science & EngineeringUniversity of CaliforniaSan DiegoUSA
  2. 2.Horst Görtz Institut für IT-SicherheitRuhr-Universität BochumGermany
  3. 3.School of Computer Science, College of ComputingGeorgia Institute of TechnologyUSA
  4. 4.Department of Computer ScienceUniversity of Texas at AustinUSA

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