A System-Oriented Approach to Full-Text Search on Encrypted Cloud Storage

Today´s Cloud market offers a wide variety of online storage services which provide reliable and inexpensive storage accessible from almost every device at almost any location. Still, it proofs to be difficult to satisfy the user´s confidence concerning the confidentiality and integrity of the own data in the Cloud. This is especially true since the user is forced to take a tradeoff between security and functionality. Storage services which allow the adoption of self-selected and self-controlled security mechanisms provide a high security level but miss on the other side a set of useful operations such as e.g. a full-text search or a synchronization across distinct devices. Such features require that the server-side is capable of accessing the data in unencrypted form for processing purposes. This paper presents an system-oriented approach to this issue by introducing an architecture that allows to integrate a full-text search operation with file-based Cloud storage services in the presence of user-selected and user-controlled security. Different instances of the presented architecture allow furthermore for a more fine-grained balance between the level of security and the provided functionality by the Cloud storage service.