Cryptology ePrint Archive: Report 2016/622

Function-Revealing Encryption

Marc Joye and Alain Passelègue

Abstract: Multi-input functional encryption is a paradigm that allows an authorized user to compute a certain function---and nothing more---over multiple plaintexts given only their encryption. The particular case of two-input functional encryption has very exciting applications, including comparing the relative order of two plaintexts from their encrypted form (order-revealing encryption).

While being extensively studied, multi-input functional encryption is not ready for a practical deployment, mainly for two reasons. First, known constructions rely on heavy cryptographic tools such as multilinear maps. Second, their security is still very uncertain, as revealed by recent devastating attacks.

In this work, we investigate a simpler approach towards obtaining practical schemes for functions of particular interest. We introduce the notion of function-revealing encryption, a generalization of order-revealing encryption to any multi-input function as well as a relaxation of multi-input functional encryption. We then propose a simple construction of order-revealing encryption based on function-revealing encryption for simple functions, namely orthogonality testing and intersection cardinality. Our main result is an efficient order-revealing encryption scheme with limited leakage based on the standard DLIN assumption.

Category / Keywords: Order-revealing encryption; property-preserving encryption; multi-input functional encryption; function-revealing encryption

Date: received 15 Jun 2016, last revised 16 Apr 2018

Contact author: alapasse at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20180416:232045 (All versions of this report)

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