Efficient Dynamic Searchable Encryption with Forward Privacy

TL;DR

This paper introduces an efficient dynamic searchable encryption scheme that ensures forward privacy, preventing linkage of new files to previous searches, and demonstrates practical performance on large datasets.

Contribution

A novel dynamic SSE scheme with forward privacy that is more efficient and parallelizable than previous solutions, with formal security proof.

Findings

Outperforms previous forward-private schemes in efficiency

Achieves search times of about one second for large datasets

Provides a formal security proof in the random oracle model

Abstract

Searchable symmetric encryption (SSE) enables a client to perform searches over its outsourced encrypted files while preserving privacy of the files and queries. Dynamic schemes, where files can be added or removed, leak more information than static schemes. For dynamic schemes, forward privacy requires that a newly added file cannot be linked to previous searches. We present a new dynamic SSE scheme that achieves forward privacy by replacing the keys revealed to the server on each search. Our scheme is efficient and parallelizable and outperforms the best previous schemes providing forward privacy, and achieves competitive performance with dynamic schemes without forward privacy. We provide a full security proof in the random oracle model. In our experiments on the Wikipedia archive of about four million pages, the server takes one second to perform a search with 100,000 results.