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Paper: Realizing Chosen Ciphertext Security Generically in Attribute-Based Encryption and Predicate Encryption

Authors:
Venkata Koppula
Brent Waters
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DOI: 10.1007/978-3-030-26951-7_23
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Abstract: We provide generic and black box transformations from any chosen plaintext secure Attribute-Based Encryption (ABE) or One-sided Predicate Encryption system into a chosen ciphertext secure system. Our transformation requires only the IND-CPA security of the original ABE scheme coupled with a pseudorandom generator (PRG) with a special security property.In particular, we consider a PRG with an n bit input $$s \in \{0,1\}^n$$ and $$n \cdot \ell $$ bit output $$y_1, \ldots , y_n$$ where each $$y_i$$ is an $$\ell $$ bit string. Then for a randomly chosen s the following two distributions should be computationally indistinguishable. In the first distribution $$r_{s_i, i} = y_i$$ and $$r_{\bar{s}_i, i}$$ is chosen randomly for $$i \in [n]$$. In the second distribution all $$r_{b, i}$$ are chosen randomly for $$i \in [n], b \in \{0,1\}$$.We show that such PRGs can be built from either the computational Diffie-Hellman assumption (in non-bilinear groups) or the Learning with Errors (LWE) assumption (and potentially other assumptions). Thus, one can transform any IND-CPA secure system into a chosen ciphertext secure one by adding either assumption. (Or by simply assuming an existing PRG is hinting secure.) In addition, our work provides a new approach and perspective for obtaining chosen ciphertext security in the basic case of public key encryption.
BibTeX
@article{crypto-2019-29902,
  title={Realizing Chosen Ciphertext Security Generically in Attribute-Based Encryption and Predicate Encryption},
  booktitle={Advances in Cryptology – CRYPTO 2019},
  series={Lecture Notes in Computer Science},
  publisher={Springer},
  volume={11693},
  pages={671-700},
  doi={10.1007/978-3-030-26951-7_23},
  author={Venkata Koppula and Brent Waters},
  year=2019
}