In this work we present FAPRIL, a privacy-preserving indoor localization scheme, which takes advantage of the latest secure two-party computation protocol improvements. We can split our scheme into two parts: an input independent setup phase and an online phase. We concentrate on optimizing the online phase for mobile clients who run on a mobile data plan and observe that recurring operands allow to optimize the total communication overhead even further. Our observation can be generalized, e.g., to improve multiplication of Arithmetic secret shared matrices. We implement FAPRIL on mobile devices and our benchmarks over a simulated LTE network show that the online phase of a private localization takes under 0.15 seconds with less than 0.20 megabytes of communication even for large buildings. The setup phase, which can be pre-computed, depends heavily on the setting but stays in the range 0.28 - 4.14 seconds and 0.69 - 16.00 megabytes per localization query. The round complexity of FAPRIL is constant for both phases.
Category / Keywords: applications / fingerprint-based localization, indoor localization, location privacy, data privacy, secure two-party computation, smartphones Original Publication (with minor differences): 19. International Conference on Security and Cryptography (SECRYPT’22) Date: received 9 May 2022 Contact author: nieminen at encrypto cs tu-darmstadt de Available format(s): PDF | BibTeX Citation Version: 20220510:082323 (All versions of this report) Short URL: ia.cr/2022/564