Web search engines such as Google, Yahoo and Microsoft Live Search are normally used to find certain data among huge amount of information in a negligible amount of time. Personalized search is a better way to improve the accuracy of web search and it has been attracting much more attention in recent times. Efficient personalized search requires collecting and aggregating user information, which can raises serious worries of privacy violation for many users. However, users are not comfortable with showing theirs private information to search engines.