Data integration involves combining data from multiple sources and providing users with a unified query interface. Data integrity has been a key problem in online data integration. Although a variety of techniques have been proposed to address the data consistency and reliability issues, there is little work on assuring the integrity of integrated data and the correctness of query results. In this paper, we take the first step to propose authenticated data integration services to ensure data and query integrity even in the presence of an untrusted integration server. We develop a novel authentication code called homomorphic secret sharing seal that can aggregate the inputs from individual sources faithfully by the untrusted server for future query authentication. Based on this, we design two authenticated index structures and authentication schemes for queries on multi-dimensional data. We further study the freshness problem in multisource query authentication and propose several advanced update strategies. Analytical models and empirical results show that our seal design and authentication schemes are efficient and robust under various system settings.