text: Cloud business intelligence is an increasingly popular choice to deliver decision support capabilities via elastic, pay-per-use resources. However, data security issues are one of the top concerns when dealing with sensitive data. In this paper, we propose a novel approach for securing cloud data warehouses by flexible verifiable secret sharing, fVSS. Secret sharing encrypts and distributes data over several cloud service providers, thus enforcing data privacy and availability. fVSS addresses four shortcomings in existing secret sharing-based approaches. First, it allows refreshing the data warehouse when some service providers fail. Second, it allows on-line analysis processing. Third, it enforces data integrity with the help of both inner and outer signatures. Fourth, it helps users control the cost of cloud warehousing by balancing the load among service providers with respect to their pricing policies. To illustrate fVSS' efficiency, we thoroughly compare it with existing secret sharing-based approaches with respect to security features, querying power and data storage and computing costs.
  @cite_8: Data security in the cloud is a big concern that blocks the widespread use of the cloud for relational data management. First, to ensure data security, data confidentiality needs to be provided when data resides in storage as well as when data is dynamically accessed by queries. Prior works on query processing on encrypted data did not provide data confidentiality guarantees in both aspects. Tradeoff between secrecy and efficiency needs to be made when satisfying both aspects of data confidentiality while being suitable for practical use. Second, to support common relational data management functions, various types of queries such as exact queries, range queries, data updates, insertion and deletion should be supported. To address these issues, this paper proposes a comprehensive framework for secure and efficient query processing of relational data in the cloud. Our framework ensures data confidentiality using a salted IDA encoding scheme and column-access-via-proxy query processing primitives, and ensures query efficiency using matrix column accesses and a secure B+-tree index. In addition, our framework provides data availability and integrity. We establish the security of our proposal by a detailed security analysis and demonstrate the query efficiency of our proposal through an experimental evaluation.
  @cite_18: Security of database outsourcing, due to the untrustworthiness of service provider, is a basic challenge to have Database As a Service in a cloud computing environment. Having disparate assumptions to solve different aspects of security such as confidentiality and integrity is an obstacle for an integrated secure solution through the combination of existing approaches. Concentrating on confidentiality and integrity aspects of database outsourcing, this paper proposes an approach in which each attribute value is split up between several data servers using a customized threshold secret sharing scheme. Our approach preserves data confidentiality and at the same time provides the correctness verifiability of query results for clients. The distribution algorithm and redundant shares in the secret sharing scheme are the basis of correctness verification for query results.
  @cite_20: Outsourced databases provide a solution for data owners who want to delegate the task of answering database queries to third-party service providers. However, distrustful users may desire a means of verifying the integrity of responses to their database queries. Simultaneously, for privacy or security reasons, the data owner may want to keep the database hidden from service providers. This security property is particularly relevant for aggregate databases, where data is sensitive, and results should only be revealed for queries that are aggregate in nature. In such a scenario, using simple signature schemes for verification does not suffice. We present a solution in which service providers can collaboratively compute aggregate queries without gaining knowledge of intermediate results, and users can verify the results of their queries, relying only on their trust of the data owner. Our protocols are secure under reasonable cryptographic assumptions, and are robust to collusion among k dishonest service providers.
  @cite_11: 
summary: In the second family of approaches @cite_11 @cite_18 @cite_20 @cite_8 , one or more additional index servers, located at @math , store B++ tree indices and signatures (Figure ). The index servers require higher security and computing power than that of other nodes, and a secure connection to the user's. The index servers support data verification by various means, i.e., homomorphic encryption @cite_18 , a hash function @cite_20 and checksums and a hash function @cite_8 . However, data verification cannot take place if the index server fails.