Cryptology ePrint Archive: Report 2015/1136

Multi-Input Functional Encryption for Unbounded Arity Functions

Saikrishna Badrinarayanan and Divya Gupta and Abhishek Jain and Amit Sahai

Abstract: The notion of multi-input functional encryption (MI-FE) was recently introduced by Goldwasser et al. [EUROCRYPT’14] as a means to non-interactively compute aggregate information on the joint private data of multiple users. A fundamental limitation of their work, however, is that the total number of users (which corresponds to the arity of the functions supported by the MI-FE scheme) must be a priori bounded and fixed at the system setup time. In this work, we overcome this limitation by introducing the notion of unbounded input MI-FE that supports the computation of functions with unbounded arity. We construct such an MI-FE scheme with indistinguishability security in the selective model based on the existence of public-coin differing-inputs obfuscation for turing machines and collision-resistant hash functions. Our result enables several new exciting applications, including a new paradigm of on-the-fly secure multiparty computation where new users can join the system dynamically.

Category / Keywords: public-key cryptography / Functional Encryption, Obfuscation

Original Publication (in the same form): IACR-ASIACRYPT-2015

Date: received 24 Nov 2015

Contact author: saikrishna at cs ucla edu

Available format(s): PDF | BibTeX Citation

Version: 20151126:193821 (All versions of this report)

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