Paper 2019/746

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, and Mariana Raykova


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 $sk_f$ 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.

Available format(s)
Public-key cryptography
Publication info
Preprint. MINOR revision.
function privacyobfuscationconjunctionssmall supersetgeneric group
Contact author(s)
bartusek james @ gmail com
bcarmer @ galois com
abhishek @ cs jhu edu
zjin12 @ jhu edu
tancrede @ google com
fermima1 @ gmail com
tal @ cs columbia edu
amaloz @ galois com
marianar @ google com
2019-06-25: received
Short URL
Creative Commons Attribution


      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},
      title = {Public-Key Function-Private Hidden Vector Encryption (and More)},
      howpublished = {Cryptology ePrint Archive, Paper 2019/746},
      year = {2019},
      note = {\url{}},
      url = {}
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