1. A method comprising: encrypting data; managing the encrypted data using a virtual machine; storing the encrypted data and a virtual machine together as a virtual machine-data image, wherein the virtual machine is configured to exert management control over the encrypted data based on policies set by an owner of the data; transferring the virtual machine-data image as a mobile agent from a first web-based service provider to a second web-based service provider; and controlling usage or movement of the data at the second web-based service provider using the virtual machine of the machine-data image.