Bluetooth is a telecommunications industry specification (an open wireless protocol) that describes how mobile phones, computers, and other accessories can be easily interconnected using a short-range wireless connection (by creating a personal area network).
HOW IT WORKS
Bluetooth enabled devices use a “frequency-hopping spread spectrum”; this allows Bluetooth to split up the data being transmitted into various “chunks” and send it on any of the 79 available frequencies (using Gaussian frequency-shift keying). By using Bluetooth, various devices (such as those listed below) are able to communicate with each other, without using wires, via the Bluetooth 2.4GHz short-range radio frequency. Bluetooth was developed by Bluetooth SIG (which consists of various companies in telecommunication, computing, and networking industries), and released in 1999 under version 1.0. In 2009, Bluetooth SIG released Bluetooth version 3.0.
For security, Bluetooth makes use of “confidentiality, authentication and key derivation” by using algorithms based on the SAFER+ block cipher. Bluetooth enabled devices will generally prompt you to enter a Bluetooth PIN which it uses as sort of a password as encryption. The devices must then be paired with each other (by using an algorithm as a key).
Bluetooth is a very short range form of communication, so somebody would have to be in very close proximity to you in order to get any data from you. Though it is possible for someone like a hacker to to “hijack” your phone via Bluetooth; this can be stopped by switching your phone to undiscoverable mode.
If you have a cell phone that’s Bluetooth enabled, you can add a short message to your Bluetooth contact. You can then find other people in the area that have their Bluetooth on discoverable mode, and send them this “secret” message (i.e. “You’ve just been Bluejacked”). People have been known to do this at malls and other places where people may be congregated in large amounts. To avoid Bluejacking, all you need to do is simply switch your Bluetooth device to undiscoverable mode or do not specifically identify yourself on your Bluetooth settings.
Bluetooth headsets are responsible for making people look like their muttering to themselves in public.