The major setback of the cloud is its inability to induce strong trust in its users. For us, the users of the cloud, to be sure of the... Show moreThe major setback of the cloud is its inability to induce strong trust in its users. For us, the users of the cloud, to be sure of the security of the data from other users, we have to trust cloud. In most of the cases, say if the data were to be hosted on Microsoft’s servers, we can trust Microsoft in its policies to prevent unauthorized access to it from other users (via hacking). But, the issue that is haunting the cloud is this - ”How can we be sure that our data is safe from Cloud service providers themselves?” The most intuitive solution for the cloud service provider to gain trust is to insist we encrypt our data. That is an irrefutable act of honesty from the cloud. But this has some obvious setbacks, few of which would negate the very advantages of cloud. One such issue that dictates the scope of this thesis is this - Typical cryptographic algorithms are not amenable to search. Now, if we were to implement a search engine on cloud (which has the data encrypted), the native search techniques have to be extended on to the cryptographic domain so that the cloud can perform the tasks of a search engine. This thesis explores the solutions to the above mentioned problem of searching over encrypted data, specifically using a secure pre-processed index approach. Though significant ideas have been proposed in the area, there is no concrete implementation to analyze if it can be used in the industrial setting. The main goal of the thesis is to implement a system which supports a variety of searching techniques. We make use of Amazon EC2 and test out the designed systems to evaluate how feasible they are for immediate consumption by the industry. M.S. in Computer Engineering, May 2011 Show less