Security as a Service using Data Steganography in Cloud

In cloud era as the data stored is away from the user, privacy and integrity of the data plays a crucial role. This paper proposes a practical and efficient method for providing security to the data stored at the data server through metadata. This method provides security using cipher key which is generated from the attributes of metadata. In this proposed model the time required for generating the cipher key is proportional to the number of attributes in the metadata as well the algorithms used for cipher key generation. Our design enforces security by providing two novel features. 1. Security is provided by the proposed model, where the encryption and decryption keys cannot be compromised without the involvement of data owner and the metadata data server (MDS), hence makes data owner comfortable about the data stored. 2. The cipher key generated using the modified feistel network holds good for the avalanche effect as each round of the feistel function depends on the previous round value. The proposed model also makes data owner reassured about the data stored at the cloud in both cases: (i) Data at Rest and (ii) Data in motion. The steganographic method used is automated based on the input from the metadata server and the user. We have implemented a security model incorporating these ideas and have evaluated the performance and scalability of the proposed model.