Unbounded inner product functional encryption from bilinear maps

Junichi Tomida, Katsuyuki Takashima

Research output: Contribution to journalArticlepeer-review

Abstract

Inner product functional encryption (IPFE) is one class of functional encryption supporting only inner product functionality. All previous IPFE schemes are bounded schemes, meaning that the vector length that can be handled in the scheme is fixed in the setup phase. In this paper, we propose the first unbounded IPFE schemes, in which we do not have to fix the lengths of vectors in the setup phase and can handle (a priori) unbounded polynomial lengths of vectors. Our first scheme is private-key based and fully function hiding. That is, secret keys hide the information of the associated function. Our second scheme is public-key based and provides adaptive security in the indistinguishability based security definition. Both our schemes are based on SXDH, which is a well-studied standard assumption, and secure in the standard model. Furthermore, our schemes are quite efficient, incurring an efficiency loss by only a small constant factor from previous bounded function hiding schemes.

Original languageEnglish
Pages (from-to)723-779
Number of pages57
JournalJapan Journal of Industrial and Applied Mathematics
Volume37
Issue number3
DOIs
Publication statusPublished - 2020 Sep 1
Externally publishedYes

Keywords

  • Bilinear maps
  • Function hiding
  • Functional encryption
  • Inner product
  • Unbounded

ASJC Scopus subject areas

  • Engineering(all)
  • Applied Mathematics

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