چکیده (انگلیسی):

With rapid development of cloud computing to a greater extent IT industries outsource their sensitive data
at cloud data storage location. To keep the stored data confidential against untrusted cloud service providers,
a natural way is to store only encrypted data in the cloud severs and providing an efficient access control
mechanism using a competent cipher key-Cmxn, which is becoming a promising cryptographic solution. In
this proposed model the cipher key is generated based on attributes of metadata. The key problems of this
approach includes, the generation of cipher key-Cmxn and establishing an access control mechanism for the
encrypted data using cipher key, where keys cannot be revoked without the involvement of data owner and
the Metadata Data Server (MDS), hence makes data owner feels comfortable about the data stored. From
this study, we propose a novel Metadata driven efficient key generation and distribution policies for cloud
data security system by exploiting the characteristic of the metadata stored. Our design enforces security by
providing two novel features. 1. Generation of Cipher key-Cmxn using modified feistel network, which holds
good for the avalanche effect as each round of the feistel function, depends on the previous round. 2. A
novel key distribution policy is designed 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. We have implemented a security model that incorporates our ideas and
evaluated the performance and scalability of the secured model.