Cryptology ePrint Archive: Report 2013/727

Multi-Input Functional Encryption

Shafi Goldwasser and Vipul Goyal and Abhishek Jain and Amit Sahai

Abstract: We introduce the problem of Multi-Input Functional Encryption, where a secret key SK_f can correspond to an n-ary function f that takes multiple ciphertexts as input. Multi-input functional encryption is a general tool for computing on encrypting data which allows for mining aggregate information from several different data sources (rather than just a single source as in single input functional encryption). We show wide applications of this primitive to running SQL queries over encrypted database, non-interactive differentially private data release, delegation of computation, etc.

We formulate both indistinguishability-based and simulation-based definitions of security for this notion, and show close connections with indistinguishability and virtual black-box definitions of obfuscation. Assuming indistinguishability obfuscation for circuits, we present constructions achieving indistinguishability security for a large class of settings. We show how to modify this construction to achieve simulation-based security as well, in those settings where simulation security is possible. Assuming differing-inputs obfuscation [Barak et al., FOCS'01], we also provide a construction with similar security guarantees as above, but where the keys and ciphertexts are compact.

Category / Keywords: public-key cryptography / functional encryption, obfuscation

Date: received 5 Nov 2013

Contact author: abhishek at csail mit edu

Available format(s): PDF | BibTeX Citation

Version: 20131113:052122 (All versions of this report)

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