Is it possible to protect confidential information within а cloud?

The direction of cloud computing protection development is considered in the article. It is suggested to consider the structure of a queuing system based on processing data centers (PDC), as the combination of six components: the hardware PDC element; telecommunication PDC resources access element; users and the software associated to them; the «middle» PDC layer, providing calculating virtualization and including control system; application services, provided by PDC as the layer of application software for guest operating systems; data storage systems, especially databases. The ways of data protection in every subsystem, the directions of necessary development and the possibility of different security levels provision are discussed in the article. According to the author, the most complicated objective is to certify access control system in modern database systems like Oracle and DB-2.