International Association for Cryptologic Research

International Association
for Cryptologic Research


Combiners for Functional Encryption, Unconditionally

Aayush Jain , UCLA
Nathan Manohar , UCLA
Amit Sahai , UCLA
DOI: 10.1007/978-3-030-45721-1_6 (login may be required)
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Presentation: Slides
Conference: EUROCRYPT 2020
Abstract: 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.
Video from EUROCRYPT 2020
  title={Combiners for Functional Encryption, Unconditionally},
  booktitle={39th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Zagreb, Croatia, May 10–14, 2020, Proceedings},
  series={Lecture Notes in Computer Science},
  keywords={Cryptographic combiners;Functional encryption},
  author={Aayush Jain and Nathan Manohar and Amit Sahai},