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Paper: Chosen-Ciphertext Secure Identity-Based Encryption in the Standard Model with short Ciphertexts

Authors:
Eike Kiltz
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URL: http://eprint.iacr.org/2006/122
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Abstract: We describe a practical identity-based encryption scheme that is secure in the standard model against chosen-ciphertext (CCA2) attacks. Security is based on an assumption comparable to (but slightly stronger than) Bilinear Decisonal Diffie-Hellman (BDDH). A comparison shows that our construction outperforms all known identity-based encryption schemes in the standard model and its performance is even comparable with the one from the random-oracle based Boneh/Franklin IBE scheme. Our proposed IBE scheme has furthermore the property that it fulfills some notion of ``redundancy-freeness", i.e. the encryption algorithm is not only a probabilistic injection but also a surjection. As a consequence the ciphertext overhead is nearly optimal: to encrypt $k$ bit messages for $k$ bit identities and with $k$ bit randomness we get $3k$ bit ciphertexts to guarantee (roughly) $k$ bits of security.
BibTeX
@misc{eprint-2006-21615,
  title={Chosen-Ciphertext Secure Identity-Based Encryption in the Standard Model with short Ciphertexts},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / Chosen-ciphertext security, Identity-Based Encryption, Bilinear Maps},
  url={http://eprint.iacr.org/2006/122},
  note={ kiltz@cwi.nl 14202 received 28 Mar 2006, last revised 19 Nov 2008},
  author={Eike Kiltz},
  year=2006
}