International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Construction of a Hybrid (Hierarchical) Identity-Based Encryption Protocol Secure Against Adaptive Attacks

Palash Sarkar
Sanjit Chatterjee
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Abstract: The current work considers the problem of obtaining a hierarchical identity-based encryption (HIBE) protocol which is secure against adaptive key extraction and decryption queries. Such a protocol is obtained by modifying an earlier protocol by Chatterjee and Sarkar (which, in turn, is based on a protocol due to Waters) which is secure only against adaptive key extraction queries. The setting is quite general in the sense that random oracles are not used and security is based on the hardness of the decisional bilinear Diffie-Hellman (DBDH) problem. In this setting, the new construction provides the most efficient (H)IBE protocol known till date. The technique for answering decryption queries in the proof is based on earlier work by Boyen, Mei and Waters. Ciphertext validity testing is done indirectly through a symmetric authentication algorithm in a manner similar to the Kurosawa-Desmedt public key encryption protocol. Additionally, we perform symmetric encryption and authentication by a single authenticated encryption algorithm.
  title={Construction of a Hybrid (Hierarchical) Identity-Based Encryption Protocol Secure Against Adaptive Attacks},
  booktitle={IACR Eprint archive},
  keywords={Hierarchical Identity based encryption, CCA-security, pairing},
  note={An abridged version of this paper has appeared in the proceedings of ProvSec 2007 13945 received 24 Oct 2006, last revised 6 Mar 2008},
  author={Palash Sarkar and Sanjit Chatterjee},