6. Bluetooth Security

6.4 Device Trust Levels

Bluetooth is designed to maintain trust levels:

1. Trusted Device: A device that has been previously authenticated, a link key is stored and is marked as "trusted" in the Device Database.  Such devices have unrestricted access to all services.
2. Untrusted Device: A device that has been previously authenticated, a link key is stores but is not marked as "trusted" in the Device Database.
3. Unknown Device: No information is available for this device. Such devices are also untrusted devices.

Verification of Device Trust Level is done by the authentication procedure (Figure 7).