Paper Title
Secured Data Storage In Cloud Environment Using Time Varying Secret Key

the key approach to secure the data stored in cloud computing environment is to store the data in encrypted manner. Whenever an authorized user wishes to store data on the cloud, the data is first encrypted and then the decryption key is distributed to other authorized users. The other authorized users can decrypt the data with the decryption key. But to prevent the revoked authorized users from accessing the data, the owner of the data will command to re-encrypt the data and distribute new decryption key to the other authorized users. This will ensure that the data remain accessible to other authorized users. However, as the cloud computing environment is composed of many cloud servers, the unreliability of the network communication proves to be a bottleneck for execution of such commands by all of the cloud servers. The existing solution to this problem requires all the data on the cloud to be re-encrypted periodically, but this could prove to be resource costly as the cloud servers store huge amount of data. Here, we propose a solution to this problem by introducing the concept of time- changing secret key for each data along with the encryption and decryption keys, which allows fine grain access control and does not require the periodic re-encryption of the data.