7 - 2 MC67 User Guide
The Bluetooth radio in this MC67 operates as a Class 2 device power class. The maximum output power is
2.5mW and the expected range is 10 meters (32 feet). A definition of ranges based on power class is difficult to
obtain due to power and device differences, and whether one measures open space or closed office space.
The current Bluetooth specification defines security at the link level. Application-level security is not specified.
This allows application developers to define security mechanisms tailored to their specific need. Link-level
security occurs between devices, not users, while application-level security can be implemented on a per-user
basis. The Bluetooth specification defines security algorithms and procedures needed to authenticate devices,
and if needed, encrypt the data flowing on the link between the devices. Device authentication is a mandatory
feature of Bluetooth while link encryption is optional.
Pairing of Bluetooth devices is accomplished by creating an initialization key that is used to authenticate the
devices and create a link key for them. Entering a common Personnel Identification Number (PIN) number in
the devices being paired generates the initialization key. The PIN number is never sent over the air. By default,
the Bluetooth stack responds with no key when a key is requested (it is up to user to respond to the key
request event). Authentication of Bluetooth devices is based-upon a challenge-response transaction. Bluetooth
allows for a PIN number or passkey that is used to create other 128-bit keys used for security and encryption.
The encryption key is derived from the link key used to authenticate the pairing devices. Also worthy of note is
the limited range and fast frequency hopping of the Bluetooth radios that makes long-distance eavesdropping
Perform pairing in a secure environment
Keep PIN codes private and don't store the PIN codes in the mobile computer
Implement application-level security.
The Microsoft stack supports Smart-pairing. For detailed information, refer to the Microsoft MSDN.
Security Mode 3 (Link Level Encryption)
The MC67 supports Security Level 3 (Link Level Encryption). Link level encryption is the data security process
of encrypting information at the data link level as it is transmitted between two devices.
Microsoft Bluetooth Stack
When pairing with a remote device using the Microsoft Bluetooth UI, Security Level 3 (Link Level Encryption) is
automatically used. When developing applications using the Microsoft Bluetooth stack, enable Security Mode 3
using the BthSetEncryption API call. Refer to the Microsoft MSDN for more information.
StoneStreet One Bluetooth Stack
To set Security Mode 3 on outgoing serial port connections, set Encrypt Link On All Outgoing Connections
checkbox in the Settings > Security. See Security on page 7-39 for more information.
NOTE It is not recommended to perform Bluetooth wireless technology inquiry when high rate 802.11b
operation is required.