International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Public-Key Function-Private Hidden Vector Encryption (and More)

James Bartusek
Brent Carmer
Abhishek Jain
Zhengzhong Jin
Tancrède Lepoint
Fermi Ma
Tal Malkin
Alex J. Malozemoff
Mariana Raykova
DOI: 10.1007/978-3-030-34618-8_17
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Abstract: We construct public-key function-private predicate encryption for the “small superset functionality,” recently introduced by Beullens and Wee (PKC 2019). This functionality captures several important classes of predicates:Point functions. For point function predicates, our construction is equivalent to public-key function-private anonymous identity-based encryption.Conjunctions. If the predicate computes a conjunction, our construction is a public-key function-private hidden vector encryption scheme. This addresses an open problem posed by Boneh, Raghunathan, and Segev (ASIACRYPT 2013).d-CNFs and read-once conjunctions of d-disjunctions for constant-size d. Our construction extends the group-based obfuscation schemes of Bishop et al. (CRYPTO 2018), Beullens and Wee (PKC 2019), and Bartusek et al. (EUROCRYPT 2019) to the setting of public-key function-private predicate encryption. We achieve an average-case notion of function privacy, which guarantees that a decryption key $$\mathsf {sk} _f$$ reveals nothing about f as long as f is drawn from a distribution with sufficient entropy. We formalize this security notion as a generalization of the (enhanced) real-or-random function privacy definition of Boneh, Raghunathan, and Segev (CRYPTO 2013). Our construction relies on bilinear groups, and we prove security in the generic bilinear group model.
  title={Public-Key Function-Private Hidden Vector Encryption (and More)},
  booktitle={Advances in Cryptology – ASIACRYPT 2019},
  series={Advances in Cryptology – ASIACRYPT 2019},
  author={James Bartusek and Brent Carmer and Abhishek Jain and Zhengzhong Jin and Tancrède Lepoint and Fermi Ma and Tal Malkin and Alex J. Malozemoff and Mariana Raykova},