Team for Research in
Ubiquitous Secure Technology

Citation
"• Space-Efficient Identity Based Encryption Without Pairings". D. Boneh, C. Gentry, and M. Hamburg (eds.), FOCS, 2007.

Abstract
Identity Based Encryption (IBE) systems are often constructed using bilinear maps (a.k.a. pairings) on elliptic curves. One exception is an elegant system due to Cocks which builds an IBE based on the quadratic residuosity problem modulo an RSA composite N. The Cocks system, however, produces long ciphertexts. Since the introduction of the Cocks system in 2001 it has been an open problem to construct a space efficient IBE system without pairings. In this paper we present an IBE system in which ciphertext size is short: an encryption of an l-bit message consists of a single element in ZN plus l+1 additional bits. Security, as in the Cocks system, relies on the quadratic residuosity problem. The system is based on the theory of ternary quadratic forms and as a result, encryption and decryption are slower than in the Cocks system.

Electronic downloads

• http://crypto.stanford.edu/~dabo/abstracts/bgh.html

• HTML

   <a
  href="http://www.truststc.org/pubs/586.html"
  ><i>•	Space-Efficient Identity Based
  Encryption Without Pairings</i></a>, D. Boneh,
  C. Gentry, and M. Hamburg (eds.), FOCS, 2007.

• Plain text

   "•	Space-Efficient Identity Based
  Encryption Without Pairings". D. Boneh, C. Gentry, and
  M. Hamburg (eds.), FOCS, 2007.

• BibTeX

  @proceedings{BonehGentryHamburg07_SpaceEfficientIdentityBasedEncryptionWithoutPairings,
      title = {•	Space-Efficient Identity Based Encryption
                Without Pairings},
      editor = {D. Boneh, C. Gentry, and M. Hamburg},
      organization = {FOCS},
      year = {2007},
      abstract = {Identity Based Encryption (IBE) systems are often
                constructed using bilinear maps (a.k.a. pairings)
                on elliptic curves. One exception is an elegant
                system due to Cocks which builds an IBE based on
                the quadratic residuosity problem modulo an RSA
                composite N. The Cocks system, however, produces
                long ciphertexts. Since the introduction of the
                Cocks system in 2001 it has been an open problem
                to construct a space efficient IBE system without
                pairings. In this paper we present an IBE system
                in which ciphertext size is short: an encryption
                of an l-bit message consists of a single element
                in ZN plus l+1 additional bits. Security, as in
                the Cocks system, relies on the quadratic
                residuosity problem. The system is based on the
                theory of ternary quadratic forms and as a result,
                encryption and decryption are slower than in the
                Cocks system. },
      URL = {http://www.truststc.org/pubs/586.html}
  }
  

Posted by Jessica Gamble on 13 Mar 2009.
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