Paper 2020/154

Combiners for Functional Encryption, Unconditionally

Aayush Jain, Nathan Manohar, and Amit Sahai


Functional encryption (FE) combiners allow one to combine many candidates for a functional encryption scheme, possibly based on different computational assumptions, into another functional encryption candidate with the guarantee that the resulting candidate is secure as long as at least one of the original candidates is secure. The fundamental question in this area is whether FE combiners exist. There have been a series of works (Ananth et. al. (CRYPTO '16), Ananth-Jain-Sahai (EUROCRYPT '17), Ananth et. al (TCC '19)) on constructing FE combiners from various assumptions. We give the first unconditional construction of combiners for functional encryption, resolving this question completely. Our construction immediately implies an unconditional universal functional encryption scheme, an FE scheme that is secure if such an FE scheme exists. Previously such results either relied on algebraic assumptions or required subexponential security assumptions.

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Publication info
A minor revision of an IACR publication in EUROCRYPT 2020
Cryptographic combinersFunctional encryption
Contact author(s)
aayushjain @ cs ucla edu
nmanohar @ cs ucla edu
sahai @ cs ucla edu
2020-02-13: received
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Creative Commons Attribution


      author = {Aayush Jain and Nathan Manohar and Amit Sahai},
      title = {Combiners for Functional Encryption, Unconditionally},
      howpublished = {Cryptology ePrint Archive, Paper 2020/154},
      year = {2020},
      note = {\url{}},
      url = {}
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