Literature study on k-nearest neighbor query processing

User´s locations and there interested are different. Collecting large amount of data to the user is very difficult. Sometime information is very sensitive; handling the information is very difficult task. Information storage also very big issue.so data owner does not make data accessible in all customers. It´s allowed only paying customers. User send their current location points and want to know about nearest POIs in NN but data Owner does not have that much storage capacity so we are using cloud service. Cloud provides power full storage at low cost but Cloud is not fully trusted. So allow processing of NN queries in an untrusted outsourced environment, whereas at an equivalent time protective each the POI and querying users´ positions. Our techniques based on mutable order preserving encoding (mOPE). It is a secure order-preserving encryption. We provide performance optimizations to decrease the computational cost.