International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Hierarchical Identity Based Encryption with Constant Size Ciphertext

Dan Boneh
Xavier Boyen
Eu-Jin Goh
Search ePrint
Search Google
Abstract: We present a Hierarchical Identity Based Encryption (HIBE) system where the ciphertext consists of just three group elements and decryption requires only two bilinear map computations, independent of the hierarchy depth. Encryption is as efficient as in other HIBE systems. We prove that the scheme is selective-ID secure in the standard model and fully secure in the random oracle model. Our system has a number of applications: it gives very efficient forward secure public key and identity based cryptosystems (where ciph ertexts are short), it converts the NNL broadcast encryption system into an efficient public key broadcast system, and it provides an efficient mechanism for encrypting to the future. The system also supports limited delegation where users can be given restricted private keys that only allow delegation to certain descendants. Sublinear size private keys can also be achieved at the expense of some ciphertext expansion.
  title={Hierarchical Identity Based Encryption with Constant Size Ciphertext},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / Identity Based Encryption},
  note={Full version. Proceedings version at 13174 received 20 Jan 2005, last revised 25 Jan 2006},
  author={Dan Boneh and Xavier Boyen and Eu-Jin Goh},