Enabling search over encrypted multimedia databases

Performing information retrieval tasks while preserving data condentiality is a desirable capability when a database is stored on a server maintained by a third-party service provider. This paper addresses the problem of enabling content-based retrieval over encrypted multimedia databases. Search indexes, along with multimedia documents, are rst encrypted by the content owner and then stored onto the server. Through jointly apply- ing cryptographic techniques, such as order preserving encryption and randomized hash functions, with image processing and information retrieval techniques, secure indexing schemes are designed to provide both privacy protection and rank-ordered search capability. Retrieval results on an encrypted color image database and se- curity analysis of the secure indexing schemes under dierent attack models show that data condentiality can be preserved while retaining very good retrieval performance. This work has promising applications in secure multimedia management.