International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Efficient Selective-ID Secure Identity Based Encryption Without Random Oracles

Dan Boneh
Xavier Boyen
Search ePrint
Search Google
Abstract: We construct two efficient Identity Based Encryption (IBE) systems that are selective identity secure {\em without the random oracle model} in groups equipped with a bilinear map. Selective identity secure IBE is a slightly weaker security model than the standard security model for IBE. In this model the adversary must commit ahead of time to the identity that it intends to attack, whereas in the standard model the adversary is allowed to choose this identity adaptively. The first system is based on the decisional bilinear Diffie-Hellman assumption, and extends to give a selective identity Hierarchical IBE secure without random oracles. The second system is based on a related assumption called the bilinear Diffie-Hellman inversion assumption. Applications of either system include an efficient CCA2 public key cryptosystem that supports non-interactive threshold decryption in the standard model, and a simple and practical IBE system that remains secure against full adaptive-ID attacks, under some security penalty, without random oracles.
  title={Efficient Selective-ID Secure Identity Based Encryption Without Random Oracles},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / identity-based encryption, provable security},
  note={An extended abstract appears in EUROCRYPT 2004. 12760 received 20 Jul 2004, last revised 8 Dec 2004},
  author={Dan Boneh and Xavier Boyen},