Abstract: Fog Computing is a paradigm that extends Cloud computing and services to the edge of the network. Similar to Cloud, Fog provides data, compute, storage, and application services to end-users. The motivation of Fog computing lies in a series of real scenarios, such as Smart Grid, smart traffic lights in vehicular networks and software defined networks. In this paper, we proposed a system for securing data stored in the cloud using decoy technology. In this we monitor data access in the cloud and detect abnormal data access. When unauthorised access is detected that users, activity will be tracked in log details table. Based on the activities performed by unauthorized user. Admin can have blocked or delete that user. When a new user enters into this System, he has to register first. After successfully registered, that user will get a key through mail. And during login, if the user enters wrong password continuously more than three times, he will get access and his activity will be tracked on log details table in the database. And after this, whatever activities he is doing that also will be tracked in the log table. If he downloads any file, he won’t get original file. Instead of that he will get decoy file. If a user entered correct password and he will get access. If that user wants to download any file, and he entered wrong key more than three times, in first three cases in the action column invalid will be entered and in the fourth case wrong key and that user will get decoy file. In every case, it Now will execute user behaviour algorithm. When a user edit password, he enters wrong key more than three times, then user will get message that password updated successfully. But in actual case it is not updating.

Keywords: FOG computing, Cloud computing, Decoy, Cisco, edge of network, Cloud Security.