Efficient fair content exchange in cloud computing

In cloud computing, the service providers can offer a virtualization environment and also provide applications as a service for users demands. Users in a cloud are able to access services, such as e-book purchasing provided by the service providers (like Yahoo or Google). If a cloud user attempts to exchange her/his digital contents with another users located in the other cloud, no watermarking protocol or DRM mechanism can efficiently provide the watermark exchange function in this environment. In addition, users must guarantee the exchange transaction fairly. Since the Internet is not secure, there may be an attacker to impersonate the user to perform the digital content exchange. In order to solve the above problems, we propose our novel efficient and fair digital content exchange scheme in cloud computing. Our proposed scheme can provide an efficient way for users to do mutual authentication, ownership transfer, and fair transaction.