From Single-Input to Multi-client Inner-Product Functional Encryption

  • Michel AbdallaEmail author
  • Fabrice Benhamouda
  • Romain Gay
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11923)


We present a new generic construction of multi-client functional encryption (MCFE) for inner products from single-input functional inner-product encryption and standard pseudorandom functions. In spite of its simplicity, the new construction supports labels, achieves security in the standard model under adaptive corruptions, and can be instantiated from the plain DDH, LWE, and Paillier assumptions. Prior to our work, the only known constructions required discrete-log-based assumptions and the random-oracle model. Since our new scheme is not compatible with the compiler from Abdalla et al. (PKC 2019) that decentralizes the generation of the functional decryption keys, we also show how to modify the latter transformation to obtain a decentralized version of our scheme with similar features.



This work was supported in part by the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement 780108 (FENTEC), by the ERC Project aSCEND (H2020 639554), by the French Programme d’Investissement d’Avenir under national project RISQ P141580, and by the French FUI project ANBLIC. The third author was partially supported by a Google PhD Fellowship in Privacy and Security. Part of this work was done while the second author was at IBM Research, Yorktown Heights, USA, and the third author was at École normale supérieure, Paris, France.


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Copyright information

© International Association for Cryptologic Research 2019

Authors and Affiliations

  1. 1.DIENS, École normale supérieureCNRS, PSL UniversityParisFrance
  2. 2.INRIAParisFrance
  3. 3.Algorand FoundationNew YorkUSA
  4. 4.University of CaliforniaBerkeleyUSA

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