Date Added: Mar 2013
Cloud computing is a complex infrastructure of software, hardware, processing, and storage that is available as a service. Cloud computing offers immediate access to large numbers of the world's most sophisticated supercomputers and their corresponding processing power, interconnected at various locations around the world, proffering speed in the tens of trillions of computations per second. Information in databases and software scattered around the Internet. There are many service providers in the internet, the authors can call each service as a cloud, each cloud service will exchange data with other cloud, so when the data is exchanged between the clouds, there exist the problem of security.