While Bluetooth connections have the advantage that they're automatic and wireless, they have the disadvantage of their data being vulnerable to interception along with any other data sent on low-power radio waves. In addition to the risk of other people being able to receive your sensitive information, they're also able to send you files or viruses that you're absolutely not interested in.
Different security features can be built into Bluetooth-enabled devices, with most having the ability to exchange data with "trusted devices" without having to ask for permission. When unknown gadgets try to connect to a user's gadget, the user is able to decide whether to allow or deny access. Some security measures that can be used are authorization and identification procedures, which require the user to consciously decide whether to open a file or to accept data being offered. Alternatively, the user can choose to switch the Bluetooth mode to "non-discoverable."
Some Bluetooth security problems include bluebugging, wherein hackers are able to use a Bluetooth-enabled phone belonging to someone else to place calls and send text messages without the owner being aware of it. Bluejacking is the sending of a text message to other nearby Bluetooth users who then add the sender to their address books as a contact. This contact can then send other, harmful messages that could be opened up automatically, as they're being sent from an already accepted contact. Although manufacturers of Bluetooth-enabled gadgets try to keep up with technological problems and offer firmware updates to solve the problems, they're sometimes a step or two behind the hackers. Bluetooth users, beware!