Optimal Bounded-Collusion Secure Functional Encryption
Author(s)Ananth, Prabhanjan; Vaikuntanathan, Vinod
MetadataShow full item record
We construct private-key and public-key functional encryption schemes in the bounded-key setting; that is, secure against adversaries that obtain an a-priori bounded number of functional keys (also known as the collusion bound). An important metric considered in the literature on bounded-key functional encryption schemes is the dependence of the running time of the encryption algorithm on the collusion bound Q = Q(λ) (where λ is the security parameter). It is known that bounded-key functional encryption schemes with encryption complexity growing with ε > 0, for any constant Q1-λ, implies indistinguishability obfuscation. On the other hand, in the public-key setting, it was previously unknown whether we could achieve encryption complexity growing linear with Q, also known as optimal bounded-key FE, based on well-studied assumptions. In this work, we give the first construction of an optimal bounded-key public-key functional encryption scheme under the minimal assumption of the existence of any public-key encryption scheme. Moreover, our scheme supports the class of all polynomial-size circuits. Our techniques also extend to the private-key setting. We achieve a construction of an optimal bounded-key functional encryption in the private-key setting based on the minimal assumption of one-way functions, instead of learning with errors as achieved in prior works.
DepartmentMassachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Lecture Notes in Computer Science
Springer International Publishing
Ananth, Prabhanjan and Vinod Vaikuntanathan. "Optimal Bounded-Collusion Secure Functional Encryption." TCC: Theory of Cryptography Conference, Lecture Notes in Computer Science, 11891, Springer International Publishing, 2019, 174-198. © 2019 International Association for Cryptologic Research.
Author's final manuscript