Construction of Differentially Private Summaries Over Fully Homomorphic Encryption

Shojiro Ushiyama*, Tsubasa Takahashi, Masashi Kudo, Hayato Yamana

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


Cloud computing has garnered attention as a platform of query processing systems. However, data privacy leakage is a critical problem. Chowdhury et al. proposed Cryptε, which executes differential privacy (DP) over encrypted data on two non-colluding semi-honest servers. Further, the DP index proposed by these authors summarizes a dataset to prevent information leakage while improving the performance. However, two problems persist: 1) the original data are decrypted to apply sorting via a garbled circuit, and 2) the added noise becomes large because the sorted data are partitioned with equal width, regardless of the data distribution. To solve these problems, we propose a new method called DP-summary that summarizes a dataset into differentially private data over a homomorphic encryption without decryption, thereby enhancing data security. Furthermore, our scheme adopts Li et al.’s data-aware and workload-aware (DAWA) algorithm for the encrypted data, thereby minimizing the noise caused by DP and reducing the errors of query responses. An experimental evaluation using torus fully homomorphic encryption (TFHE), a bit-wise fully homomorphic encryption library, confirms the applicability of the proposed method, which summarized eight 16-bit data in 12.5 h. We also confirmed that there was no accuracy degradation even after adopting TFHE along with the DAWA algorithm.

Original languageEnglish
Title of host publicationDatabase and Expert Systems Applications - 32nd International Conference, DEXA 2021, Proceedings
EditorsChristine Strauss, Gabriele Kotsis, A Min Tjoa, Ismail Khalil
PublisherSpringer Science and Business Media Deutschland GmbH
Number of pages13
ISBN (Print)9783030864743
Publication statusPublished - 2021
Event32nd International Conference on Database and Expert Systems Applications, DEXA 2021 - Virtual, Online
Duration: 2021 Sept 272021 Sept 30

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12924 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference32nd International Conference on Database and Expert Systems Applications, DEXA 2021
CityVirtual, Online


  • Differential privacy
  • Differentially private summary
  • Fully Homomorphic encryption
  • TFHE

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)


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