Security in mobile communication networks is an ever moving and expanding area. With political and business leaders, law enforcement services, emergency services and the military all using mobile communications routinely, the value of communications and the impact of any compromise has also grown. With new trends having been detected for the spread of viruses and worms to a broad range of digital devices and new approaches to intercepting communications, security is a rapidly growing concern in mobile communication networks. The industry and users cannot afford to be complacent. As the industry remains focused on all aspects of telecommunications security, this presentation discusses security requirements of mobile devices and services, including a case study.