Computer network security consists of the policies adopted to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources. Network security involves the authorization of access to data in a network, which is controlled by the network administrator. Users choose or are assigned an ID and password or other authenticating information that allows them access to information and programs within their authority. Network security covers a variety of computer networks, both public and private, that are used in everyday jobs; conducting transactions and communications among businesses, government agencies and individuals. Networks can be private, such as within a company, and others which might be open to public access. Network security is involved in organizations, enterprises, and other types of institutions. It does as its title explains: It secures the network, as well as protecting and overseeing operations being done.

  In the present book, thirty literatures about computer network security published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on network security, cloud computing, wireless sensor network, network confidentiality and so on. We hope this book can demonstrate advances in computer network security as well as give references to the researchers, students and other related people.