User`s manual
80
Security
Composition of Bluetooth
In the current Bluetooth speci¿cations, the security level is de¿ned to the level of link and the security level of
applications is not de¿ned. Therefore, application developers may de¿ne security mechanisms to meet speci¿c
requirements. The security at the level of applications is implemented per each user, whereas the security at the
level of link is implemented between devices. The Bluetooth speci¿cations de¿ne security algorithms and procedures
necessary to certi¿cate devices and, if necessary, to encrypt the data Àow of link between devices. The certi¿cation of
devices is a fundamental feature of Bluetooth; however, the encryption of link is selective.
The synchronization between Bluetooth devices are performed by generating initialization keys used for link keys
required for certifying devices. Basically, a Bluetooth stack responds without a key when a key is requested (the
response to the key-requesting event is the user
’
s role). The certi¿cation of Bluetooth devices are based on attempt-
response transactions. In Bluetooth technology, other PIN numbers or passwords used for generating 128 bit keys
for security and encryption can be re-used. Encrypted keys are extracted from the link keys used for certifying
synchronized devices. Also, the constraints in distance and high-speed frequency hopping of Bluetooth wireless
technology make eavesdropping dif¿cult.
Recommendations are as follows:
Synchronization should be conducted under secured environments.
Do not save PIN code at industrial PDA. Store it somewhere else personally.
Implement a security at the level of applications.
Microsoft stack supports smart synchronization. For the details, see Microsoft MSDN.
In principle, CW30 is con¿gured to use Microsoft Bluetooth stack.
The available services via Microsoft Bluetooth stack is listed in Table 6-1.
[Table 6-1. Bluetooth services]
Microsoft Bluetooth Stack
OBEX Object Push Services
Hands-Free Audio Gateway Services
Serial Port Services
Personal Area Networking Services
PBAP Services
Dial-Up Networking Services
HID Client Services
A2DP/AVRCP Services