Show simple item record

dc.contributor.advisorCanetti, Ranen_US
dc.contributor.advisorReyzin, Leoniden_US
dc.contributor.authorChen, Yileien_US
dc.date.accessioned2019-01-16T15:00:25Z
dc.date.available2019-01-16T15:00:25Z
dc.date.issued2018
dc.identifier.urihttps://hdl.handle.net/2144/33068
dc.description.abstractConstructing advanced cryptographic applications often requires the ability of privately embedding messages or functions in the code of a program. As an example, consider the task of building a searchable encryption scheme, which allows the users to search over the encrypted data and learn nothing other than the search result. Such a task is achievable if it is possible to embed the secret key of an encryption scheme into the code of a program that performs the "decrypt-then-search" functionality, and guarantee that the code hides everything except its functionality. This thesis studies two cryptographic primitives that facilitate the capability of hiding secrets in the program of random functions. 1. We first study the notion of a private constrained pseudorandom function (PCPRF). A PCPRF allows the PRF master secret key holder to derive a public constrained key that changes the functionality of the original key without revealing the constraint description. Such a notion closely captures the goal of privately embedding functions in the code of a random function. Our main contribution is in constructing single-key secure PCPRFs for NC^1 circuit constraints based on the learning with errors assumption. Single-key secure PCPRFs were known to support a wide range of cryptographic applications, such as private-key deniable encryption and watermarking. In addition, we build reusable garbled circuits from PCPRFs. 2. We then study how to construct cryptographic hash functions that satisfy strong random oracle-like properties. In particular, we focus on the notion of correlation intractability, which requires that given the description of a function, it should be hard to find an input-output pair that satisfies any sparse relations. Correlation intractability captures the security properties required for, e.g., the soundness of the Fiat-Shamir heuristic, where the Fiat-Shamir transformation is a practical method of building signature schemes from interactive proof protocols. However, correlation intractability was shown to be impossible to achieve for certain length parameters, and was widely considered to be unobtainable. Our contribution is in building correlation intractable functions from various cryptographic assumptions. The security analyses of the constructions use the techniques of secretly embedding constraints in the code of random functions.en_US
dc.language.isoen_US
dc.subjectComputer scienceen_US
dc.subjectCryptographyen_US
dc.subjectFunctional encryptionen_US
dc.subjectProgram obfuscationen_US
dc.subjectPseudorandom functionsen_US
dc.titleHiding secrets in public random functionsen_US
dc.typeThesis/Dissertationen_US
dc.date.updated2018-11-07T20:03:05Z
etd.degree.nameDoctor of Philosophyen_US
etd.degree.leveldoctoralen_US
etd.degree.disciplineComputer Scienceen_US
etd.degree.grantorBoston Universityen_US


This item appears in the following Collection(s)

Show simple item record