In general, the term “wireless” denotes any type of data communication which does not require a cable (wire). More specifically, wireless communication means data communication via radio signals. An important aspect of radio signals is that they can be picked up by anyone within the range of the sender, and hence radio signals can easily be intercepted by attackers. Secure design of wireless technologies must take this aspect into account, typically by using encryption. There are numerous technologies for wireless data communication, where some are implemented in consumer devices that we carry with us. Early generations of these radio communication technologies typically had weak security, but that has improved over the years. Wireless technologies are also used in industrial applications such as satellite links, GPS (geo-positioning systems), and fixed point-to-point radio links, where security is also integrated to a greater or lesser extent.