dc.contributor.author | Pawlega, Filip | |
dc.date.accessioned | 2018-09-20 14:46:23 (GMT) | |
dc.date.available | 2019-09-21 04:50:09 (GMT) | |
dc.date.issued | 2018-09-20 | |
dc.date.submitted | 2018-09-13 | |
dc.identifier.uri | http://hdl.handle.net/10012/13840 | |
dc.description.abstract | Privately Constrained Pseudorandom Functions allow a PRF key to be delegated to some
evaluator in a constrained manner, such that the key’s functionality is restricted with
respect to some secret predicate. Variants of Privately Constrained Pseudorandom Func-
tions have been applied to rich applications such as Broadcast Encryption, and Secret-key
Functional Encryption. Recently, this primitive has also been instantiated from standard
assumptions. We extend its functionality to a new tool we call Privately Constrained
Testable Pseudorandom functions.
For any predicate C, the holder of a secret key sk can produce a delegatable key constrained
on C denoted as sk[C]. Evaluations on inputs x produced using the constrained key differ
from unconstrained evaluations with respect to the result of C(x). Given an output y
evaluated using sk[C], the holder of the unconstrained key sk can verify whether the input
x used to produce y satisfied the predicate C. That is, given y, they learn whether C(x) = 1
without needing to evaluate the predicate themselves, and without requiring the original
input x.
We define two inequivalent security models for this new primitive, a stronger indistinguishability-
based definition, and a weaker simulation-based definition. Under the indistinguishability-
based definition, we show the new primitive implies Designated-Verifier Non-Interactive
Zero-Knowledge Arguments for NP in a black-box manner. Under the simulation-based
definition, we construct a provably secure instantiation of the primitive from lattice as-
sumptions. We leave the study of the gap between definitions, and discovering techniques
to reconcile it as future work. | en |
dc.language.iso | en | en |
dc.publisher | University of Waterloo | en |
dc.subject | cryptography | en |
dc.title | Privately Constrained Testable Pseudorandom Functions | en |
dc.type | Master Thesis | en |
dc.pending | false | |
uws-etd.degree.department | David R. Cheriton School of Computer Science | en |
uws-etd.degree.discipline | Computer Science | en |
uws-etd.degree.grantor | University of Waterloo | en |
uws-etd.degree | Master of Mathematics | en |
uws-etd.embargo.terms | 1 year | en |
uws.contributor.advisor | Gorbunov, Sergey | |
uws.contributor.advisor | Jao, David | |
uws.contributor.affiliation1 | Faculty of Mathematics | en |
uws.published.city | Waterloo | en |
uws.published.country | Canada | en |
uws.published.province | Ontario | en |
uws.typeOfResource | Text | en |
uws.peerReviewStatus | Unreviewed | en |
uws.scholarLevel | Graduate | en |