Wi-Fi (also known as 802.11b/g) is the most popular type of wireless technology for connecting computers, but there's another kind of wireless technology that has become widely usedBluetooth. It is used primarily for cell phones and personal digital assistants (PDAs), although it can also be used for wireless keyboards, mice, and headphones and for connecting computers to one another.
Bluetooth was designed so that you do not need to do anything to connect devices to one another. Simply turn on the device, and it automatically looks for another Bluetooth device. If it finds one or more such devices, they set up wireless communications between the two of them (also known as bonding).
Bluetooth is an ad hoc network, which means that not only do the devices find each other on their own, but they also can communicate directly with each other without having to go through a central device, such as a server or network access point. This kind of network, in which devices connect directly to one another, is known as a peer-to-peer network.
The most common use of Bluetooth is for cell phones. Bluetooth headsets are becoming increasingly common for cell phone users. But Bluetooth connections are frequently used to connect phones to one another, so they can exchange files, for example. And Bluetooth is also used to connect cell phones to computers for doing things such as synchronizing address books.
Because cell phones have become so common, there is a growing worry that they will become the targets of hackers, notably hacking them using Bluetooth. For more information about cell phone hacking, including a variety of Bluetooth dangers, see Chapter 22, "How Cell Phones Can Be Hacked."
The illustrations in this chapter show how Bluetooth works and how Bluetooth can be hacked. Note that any kind of Bluetooth device can be hacked in the way described in this chapter, not just cell phones. So, for example, if two people are connecting their PCs to one another via a Bluetooth connection, they can be hacked in the same way as if two people were connecting their cell phones to one another.