Secure data devolution: Practical re-encryption with auxiliary data in LWE-based somewhat homomorphic encryption

Masaya Yasuda, Takeshi Koshiba, Takeshi Shimoyama, Jun Kogure, Kazuhiro Yokoyama

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

Abstract

Homomorphic encryption can support meaningful operations on encrypted data, and hence it enables users to outsource their data in encrypted format to cloud services. However, homomorphic encryption cannot operate on ciphertexts with different keys in general. To resolve the problem, re-encryption allows operations on such ciphertexts by unifying the different keys into a new one. In this paper, we focus on the scheme proposed by Brakerski and Vaikuntanathan (CRYPTO 2011), and give a practical re-encryption method. Our strategy for efficient re-encryption is to simply rewrite the decryption circuit and then to evaluate the circuit homomorphically with auxiliary information. In particular, our method requires only a few homomorphic operations for re-encryption, and it can be applied to various applications such as secure key exchange for collaboratively computing multiple users' data in the cloud.

Original languageEnglish
Title of host publicationSCC 2015 - Proceedings of the 3rd ACM International Workshop on Security in Cloud Computing, part of ASIACCS 2015
PublisherAssociation for Computing Machinery, Inc
Pages53-61
Number of pages9
ISBN (Electronic)9781450334471
DOIs
Publication statusPublished - 2015 Apr 14
Externally publishedYes
Event3rd ACM International Workshop on Security in Cloud Computing, SCC 2015 - Singapore, Singapore
Duration: 2015 Apr 14 → …

Other

Other3rd ACM International Workshop on Security in Cloud Computing, SCC 2015
CountrySingapore
CitySingapore
Period15/4/14 → …

Keywords

  • Homomorphic encryption
  • LWE assumption
  • Re-encryption
  • Secure key exchange

ASJC Scopus subject areas

  • Software

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  • Cite this

    Yasuda, M., Koshiba, T., Shimoyama, T., Kogure, J., & Yokoyama, K. (2015). Secure data devolution: Practical re-encryption with auxiliary data in LWE-based somewhat homomorphic encryption. In SCC 2015 - Proceedings of the 3rd ACM International Workshop on Security in Cloud Computing, part of ASIACCS 2015 (pp. 53-61). Association for Computing Machinery, Inc. https://doi.org/10.1145/2732516.2732521