The development of the wireless communications environment, especially as related to security, has been relatively stable compared to the issues of fixed Internet. Nevertheless, along with the enhanced functionalities of smart devices, networks and applications, the level of malicious attacks has increased considerably. It can be estimated that security attacks, distribution of viruses and other malicious activities increase in the wireless environment along with the higher number of users. Not only are payment activities, person-to-person communications and social media utilization under constant threat, but furthermore, one of the strongly increasing security risks is related to M2M (Machine-to-Machine) communications. This book describes the current and most probable future wireless security solutions. The focus is on the technical discussion of existing systems and new trends like Internet of Things (IoT). It also discusses existing and potential security threats, presents methods for protecting systems, operators and end-users, describes security systems attack types and the new dangers in the ever-evolving Internet. The book functions as a practical guide describing the evolvement of the wireless environment, and how to ensure the fluent continuum of the new functionalities, whilst minimizing the potential risks in network security.