Guest Editorial for Special Section on Advanced Techniques for Efficient and Reliable Cloud Storage

CLOUD computing has emerged as a disruptive technology andnew computing paradigm inwhich IT resources (hardware, software, applications, data storage, computing capacity, etc.) are provided as services over the Internet, through “everything-as-a-service”. It builds on the foundations of distributed computing, grid computing, virtualization, service orientation, etc. Cloud storage, which is one of the most attractive cloud services, offers numerous benefits from both the technology and functionality perspectives such as increased availability, flexibility, functionality and costs. However, Cloud environment needs to manage data center virtualization, lower cost and boost reliability by consolidating systems in the cloud. Despite of very fast advances, the new Cloud environment creates major data management challenges such as efficient and reliable remote storage, online data query processing, outsourcing computation and secure virtualization. This special section addresses such challenging issues covering recent advances in cloud storage, with emphasis on Cloud storage service selection, Cloud data auditing, Cloud data encryption and Cloud data de-duplication. After a very rigorous review process in three rounds, four high quality papers were selected for this special section, which are arranged as follows. In the first paper “Smart Cloud Storage Service Selection Based on Fuzzy Logic, Theory of Evidence and Game Theory”, Esposito et al. present an approach for optimal selection of Cloud services fitting the customer requirements in terms of quality of service and costs. The aim is to handle uncertainty in the expression of subjective preferences from customers in presence of rational/selfish providers, exposing untrustworthy indications concerning the quality of service levels and prices associated to their offers. Fuzzy sets theory is used to express vagueness in the subjective preferences of the customers while the selection strategy is complemented by the adoption of a game theoretic approach for promoting truth-telling ones among service providers. In the second paper, “Public Integrity Auditing for Shared Dynamic Cloud Data with Secure Group User Revocation” by Jiang et al., the authors investigate secure remote data auditing to achieve secure and efficient public data integrity auditing for shared dynamic data. An efficient public integrity auditing schemewith secure groupuser revocation based on vector commitment and verifier-local revocation group signature is therefore presented, which supports the public checking and efficient user revocation and also some properties, such as confidently, efficiency, accountability and traceability of secure group user revocation. Cui et al. in the third paper, “Key-Aggregate Searchable Encryption (KASE) for Group Data Sharing via Cloud Storage”, study security concerns over inadvertent data leaks in the cloud due to the capability of selectively sharing encrypted data with different users via public cloud storage. The authors propose a novel concept of key-aggregate searchable encryption and instantiating the concept through a concrete KASE scheme, in which a data owner only needs to distribute a single key to a user for sharing a large number of documents, and the user only needs to submit a single trapdoor to the cloud for querying the shared documents. The final paper, “Secure Auditing and De-duplicating Data in Cloud” by Li et al., deals with some research issues related to data outsourcing to cloud service. In their approach their consider how to realize data deduplication in cloud while achieving integrity auditing. Aiming at achieving both data integrity and deduplication in cloud, they propose two secure systems to enable integrity auditing and secure deduplication on encrypted data. The guest editors would like to thank Prof. Albert Zomaya for the opportunity to edit this special section. The support by journal managers during the editorial process is also highly appreciated.