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Paper: Amplifying the Security of Functional Encryption, Unconditionally

Authors:
Aayush Jain , UCLA
Alexis Korb , UCLA
Nathan Manohar , UCLA
Amit Sahai , UCLA
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DOI: http://dx.doi.org/10.1007/978-3-030-56784-2_24 (login may be required)
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Presentation: Slides
Conference: CRYPTO 2020
Abstract: Security amplification is a fundamental problem in cryptography. In this work, we study security amplification for functional encryption. We show two main results: - For any constant epsilon in (0,1), we can amplify an epsilon-secure FE scheme for P/poly which is secure against all polynomial sized adversaries to a fully secure FE scheme for P/poly, unconditionally. - For any constant epsilon in (0,1), we can amplify an epsilon-secure FE scheme for P/poly which is secure against subexponential sized adversaries to a subexponentially secure FE scheme for P/poly, unconditionally. Furthermore, both of our amplification results preserve compactness of the underlying FE scheme. Previously, amplification results for FE were only known assuming subexponentially secure LWE. Along the way, we introduce a new form of homomorphic secret sharing called set homomorphic secret sharing that may be of independent interest. Additionally, we introduce a new technique, which allows one to argue security amplification of nested primitives, and prove a general theorem that can be used to analyze the security amplification of parallel repetitions.
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BibTeX
@inproceedings{crypto-2020-30451,
  title={Amplifying the Security of Functional Encryption, Unconditionally},
  publisher={Springer-Verlag},
  doi={http://dx.doi.org/10.1007/978-3-030-56784-2_24},
  author={Aayush Jain and Alexis Korb and Nathan Manohar and Amit Sahai},
  year=2020
}