Authenticated Index Structures for Aggregation Queries

Query authentication is an essential component in Outsourced DataBase (ODB) systems. This article introduces efficient index structures for authenticating aggregation queries over large datasets. First, we design an index that features good performance characteristics for static environments. Then, we propose more involved structures for the dynamic case. Our structures feature excellent performance for authenticating queries with multiple aggregate attributes and multiple selection predicates. Furthermore, our techniques cover a large number of aggregate types, including distributive aggregates (such as SUM, COUNT, MIN, and MAX), algebraic aggregates (such as the AVG), and holistic aggregates (such as MEDIAN and QUANTILE). We have also addressed the issue of authenticating aggregation queries efficiently when the database is encrypted to protect data confidentiality. Finally, we implemented a working prototype of the proposed techniques and experimentally validated the effectiveness and efficiency of our methods.