Biblio

Most centralized systems allow data access to its cloud user if a cloud user has a certain set of satisfying attributes. Presently, one method to compete such policies is to use an authorized cloud server to maintain the user data and have access control over it. At times, when one of the servers keeping data is compromised, the security of the user data is compromised. For getting access control, maintaining data security and obtaining precise computing results, the data owners have to keep attribute-based security to encrypt the stored data. During the delegation of data on cloud, the cloud servers may be tampered by the counterfeit cipher-text. Furthermore, the authorized users may be cheated by retorting them that they are unauthorized. Largely the encryption control access attribute policies are complex. In this paper, we present Cipher-text Policy Attribute-Based Encryption for maintaining complex access control over encrypted data with verifiable customizable authorization. The proposed technique provides data confidentiality to the encrypted data even if the storage server is comprised. Moreover, our method is highly secured against collusion attacks. In advance, performance evaluation of the proposed system is elaborated with implementation of the same.

Recently, Jung et al. [1] proposed a data access privilege scheme and claimed that their scheme addresses data and identity privacy as well as multi-authority, and provides data access privilege for attribute-based encryption. In this paper, we show that this scheme, and also its former and latest versions (i.e. [2] and [3] respectively) suffer from a number of weaknesses in terms of finegrained access control, users and authorities collusion attack, user authorization, and user anonymity protection. We then propose our new scheme that overcomes these shortcomings. We also prove the security of our scheme against user collusion attacks, authority collusion attacks and chosen plaintext attacks. Lastly, we show that the efficiency of our scheme is comparable with existing related schemes.

Cloud computing is an application and set of services given through the internet. However it is an emerging technology for shared infrastructure but it lacks with an access rights and security mechanism. As it lacks security issues for the cloud users our system focuses only on the security provided through the token management system. It is based on the internet where computing is done through the virtual shared servers for providing infrastructure, software, platform and security as a services. In which security plays an important role in the cloud service. Hence, this security has been given with three types of services such as mutual authentication, directory services, token granting for the resources. Since, existing token issuing mechanism does not provide scalability to large data sets and also increases memory overhead between the client and the server. Hence, our proposed work focuses on providing tokens to the users, which addresses the problem of scalability and memory overhead. The proposed framework of token management system monitors the entire operations of the cloud and there by managing the entire cloud infrastructure. Our model comes under the new category of cloud model known as "Security as a Service". This paper provides the security framework as an architectural model to verify user authorization and data correctness of the resource stored thereby provides guarantee to the data owner for their resource stored into the cloud This framework also describes about the storage of token in a secured manner and it also facilitates search and usage of tokens for auditing purpose and supervision of the users.