A Secure One-Roundtrip Index for Range Queries

We present the first one-roundtrip protocol for performing range, range-aggregate, and order-by-limit queries over encrypted data, that both provides semantic security and is efficient. We accomplish this task by chaining garbled circuits over a search tree, using branch-chained garbled circuits, as well as carefully designing garbled circuits. We then show how to build a database index that can answer order comparison queries. We implemented and evaluated our index. We demonstrate that queries as well as inserts and updates are efficient, and that our index outperforms previous interactive constructions. This index is part of the Arx database system, whose source code will be released in the near future.