Cloud is a collection encompassing a number of computers and servers that we find access to and is hosted by the internet. This technology provides capabilities for processing, storing and retrieving, support and etc. by way of the internet. Cloud computing consists of trustable services by future generation data centres that are based on virtual calculations and technologies and are provided by the internet. Now a day, numerous technologies are migrating from traditional systems to cloud. Off course, cloud can also be used as a tool for military and non-military goals. On the other hand, in this wide network where users are individuals and companies, in addition to shared use of resources, personal data is also placed in the network, need for security is very important. Frequently, users and organizations become more commonly and rapidly interested in using it when there is confidence in presence of high security methods in this service. In this paper, initially the effective role and advantages of cloud computing is evaluated in some large international military and non-military companies and organizations and ultimately security solution based on the Kalman filter is presented.