Abstract: Intrusion Detection Systems are being used in every software whether it is web based or not. But application of IDS in public networks such as cloud, grid computing has many applications and has been proven to be boon. The application of IDS is used in creating an alarming system for the networks so that security measures can be applied to prevent the possible loss of data and avoiding non functioning systems. Because of the enhanced technology there are many ways of the hacking and compromising any networked system has been evolved and causing huge loses. Since direct application of security methods affects the performance of the system heavily, therefore application of IDS is increasing widely. Since IDS can be applied on gateways therefore a quick and better alarming system can be created which will prompt the administrators to apply security techniques to avoid the problems. In this work, different IDS mechanisms have been studied and list of possible criteria has been enlisted to provide IDS over the cloud. This work also proposes to take one of the IDS mechanisms to study the criteria of IDS, their behaviours, advantages and possible alarming for Cloud.

Keywords: Cloud Computing, Security, Intrusion Detection System, Alarming criteria, abnormal behaviours, Encryption, Decryption, Authentication, Authorization, non-repudiation.