Abstract: Cloud computing is a worldwide hot topic nowadays. It will probably cause a new revolution to information technologies. But meanwhile it induces new security problems as well. Standing on the bottom layer of a cloud computing environment, this paper carried out research on security of cloud infrastructure. It observed the statcof-thcart of cloud infrastructure security, analyzed security problems existing in cloud infrastructure from a wide perspective. In combination with a technical framework of cloud infrastructure security, it discussed principle key technictues of cloud infrastructure security. The motivation of the paper is to lay a solid ground for solving security problems in cloud infrastructure as well as in the whole cloud computing environment

Key words: Cloud computing, Infrastructure, Security, Privacy, Virtualization