eSkyline: Processing Skyline Queries over Encrypted Data

The advent of cloud computing redefines the traditional query processing paradigm. Whereas computational overhead and memory constraints become less prohibitive, data privacy, security, and confidentiality concerns become top priorities. In particular, as data owners outsource the management of their data to service providers, query processing over such data has more resources to tap into, yet the data oftentimes has to be encrypted so as to prevent unauthorized access. The challenge that arises in such a setting is to devise an encryption scheme that still allows for query results to be efficiently computed using the encrypted data values. An important type of query that raises unconventional requirements in terms of the operator that has to be evaluated is the skyline query, which returns a set of objects in a dataset whose values are not dominated by any other object therein. In this demonstration, we present eSkyline, a prototype system and query interface that enables the processing of skyline queries over encrypted data, even without preserving the order on each attribute as order-preserving encryption would do. Our system comprises of an encryption scheme that facilitates the evaluation of domination relationships, hence allows for state-ofthe-art skyline processing algorithms to be used. The actual data values are reconstructed only at the client side, where the encryption key is known. Our demo visualizes the details of the encryption scheme, allows a user to interact with a server, and showcases the efficiency of computing skyline queries and decrypting the results.