On the Limitations of the Spread of an IBE-to-PKE Transformation
- 1.4k Downloads
By a generic transformation by Canetti, Halevi, and Katz (CHK) every Identity-based encryption (IBE) scheme implies a chosen-ciphertext secure public-key encryption (PKE) scheme. In the same work it is claimed that this transformation maps the two existing IBE schemes to two new and different chosen-ciphertext secure encryption schemes, each with individual advantages over the other.
In this work we reconsider one of the two specific instantiations of the CHK transformation (when applied to the “second Boneh/Boyen IBE scheme”). We demonstrate that by applying further simplifications the resulting scheme can be proven secure under a weaker assumption than the underlying IBE scheme.
Surprisingly, our simplified scheme nearly converges to a recent encryption scheme due to Boyen, Mei, and Waters which itself was obtained from the other specific instantiation of the CHK transformation (when applied to the “first Boneh/Boyen IBE scheme”). We find this particularly interesting since the two underlying IBE schemes are completely different.
The bottom line of this paper is that the claim made by Canetti, Halevi, and Katz needs to be reformulated to: the CHK transformation maps the two known IBE schemes to nearly one single encryption scheme.
KeywordsEncryption Scheme Message Authentication Code Challenge Ciphertext Choose Ciphertext Attack Bilinear Group
- 2.Boneh, D., Canetti, R., Halevi, S., Katz, J.: Chosen-ciphertext security from identity-based encryption. Accepted to SIAM Journal on Computing (January 2006)Google Scholar
- 5.Boyen, X., Mei, Q., Waters, B.: Simple and efficient CCA2 security from IBE techniques. In: ACM Conference on Computer and Communications Security—CCS 2005, pp. 320–329. ACM Press, New York (2005)Google Scholar
- 7.Cramer, R., Shoup, V.: A practical public key cryptosystem provably secure against adaptive chosen ciphertext attack. In: Krawczyk, H. (ed.) CRYPTO 1998. LNCS, vol. 1462, pp. 13–25. Springer, Heidelberg (1998)Google Scholar
- 9.Dolev, D., Dwork, C., Naor, M.: Non-malleable cryptography. In: 23rd ACM STOC, May 1991, pp. 542–552. ACM Press, New York (1991)Google Scholar
- 12.Naor, M., Yung, M.: Universal one-way hash functions and their cryptographic applications. In: 21st ACM STOC, May 1989, pp. 33–43. ACM Press, New York (1989)Google Scholar
- 13.Naor, M., Yung, M.: Public-key cryptosystems provably secure against chosen ciphertext attacks. In: 22nd ACM STOC, May 1990. ACM Press, New York (1990)Google Scholar
- 14.Rackoff, C., Simon, D.R.: Non-interactive zero-knowledge proof of knowledge and chosen ciphertext attack. In: Feigenbaum, J. (ed.) CRYPTO 1991. LNCS, vol. 576, pp. 433–444. Springer, Heidelberg (1991)Google Scholar
- 15.Rompel, J.: One-way functions are necessary and sufficient for secure signatures. In: 22nd ACM STOC, May 1990, pp. 387–394. ACM Press, New York (1990)Google Scholar