Security of Data Fragmentation and Replication over Un-trusted Hosts

Data replication technique is used to avoid the fault tolerance and improve the performance .With this initiation of content delivery networks, it is becoming more and more frequent that data content is placed on hosts that are not directly controlled by the content owner, and due to this, to ensure the data integrity ,security mechanism are needed. In this paper we present a system architecture that allows arbitrary queries to be supported on data content replicated over un-trusted servers. To prevent these servers from returning incorrect answers to client, we make use of a small number of trusted hosts that randomly check these answers and take corrective action whenever required. Additionally, our system will use an audit mechanism that guarantees that any un-trusted server acting maliciously will finally be detected and excluded from the system so that the consistency can be maintained.