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(F)unctional Sifting: A Privacy-Preserving Reputation System Through Multi-Input Functional Encryption

Bakas, Alexandros; Michalas, Antonis; Ullah, Amjad

Authors

Alexandros Bakas

Antonis Michalas



Abstract

Functional Encryption (FE) allows users who hold a specific secret key (known as the functional key) to learn a specific function of encrypted data whilst learning nothing about the content of the underlying data. Considering this functionality and the fact that the field of FE is still in its infancy, we sought a route to apply this potent tool to solve the existing problem of designing decentralised additive reputation systems. To this end, we first built a symmetric FE scheme for the ℓ1 norm of a vector space, which allows us to compute the sum of the components of an encrypted vector (i.e. the votes). Then, we utilized our construction, along with functionalities offered by Intel SGX, to design the first FE-based decentralized additive reputation system with Multi-Party Computation. While our reputation system faces certain limitations, this work is amongst the first attempts that seek to utilize FE in the solution of a real-life problem.

Citation

Bakas, A., Michalas, A., & Ullah, A. (2021). (F)unctional Sifting: A Privacy-Preserving Reputation System Through Multi-Input Functional Encryption. In Secure IT Systems: 25th Nordic Conference, NordSec 2020, Virtual Event, November 23--24, 2020, Proceedings 25 (111-126). https://doi.org/10.1007/978-3-030-70852-8_7

Conference Name Secure IT Systems 25th Nordic Conference, NordSec 2020
Conference Location Online
Start Date Nov 23, 2020
End Date Nov 24, 2020
Online Publication Date Mar 3, 2021
Publication Date 2021
Deposit Date Jul 27, 2021
Publisher Springer
Pages 111-126
Series Title Lecture Notes in Computer Science
Series Number 12556
Series ISSN 0302-9743
Book Title Secure IT Systems: 25th Nordic Conference, NordSec 2020, Virtual Event, November 23--24, 2020, Proceedings 25
DOI https://doi.org/10.1007/978-3-030-70852-8_7
Public URL http://researchrepository.napier.ac.uk/Output/2789406