Ensuring Data Privacy and Access Anonymity using Cryptographic Techniques in Cloud Computing

the main idea behind Cloud computing is to store data and other resources remotely in the cloud and accessed it anytime from anywhere through devices such as mobile devices, laptops and personal computers and any other thin client devices. This offers many advantages, like data ubiquity, flexibility of access, better performance and low start up cost. This in many ways improves the security as the cloud service provider is able to invest more in enforcing up-to date security technologies and practices than the data owner. However, this introduces new challenges with respect to ensuring the data security and the privacy. The main threat or disadvantage is that the data owner solely depends on the trustworthiness of the service provider who may not always be trustworthy. Thus, there is the need to ensure that customers data privacy and integrity are maintained. Secure access control policies, data integrity check and data privacy techniques to hide the data from the service provider needs to be implemented. Simply encrypting the data is inefficient and is vulnerable to attacks when the access control policies change. Several techniques have been proposed to address these privacy issues. Approaches based on two layers of encryption alleviate the privacy concern the disadvantage of this technique is that it still require re-encryption of the data when there is a change in the access policies. This paper presents a novel and efficient solution that employs two layers of encryption of the data and an encrypted data object containing the second access key. Changes to the access control policies are handled by re-encrypting the object containing the affected key, which is an efficient operation compared to re-encrypting the whole data or information.