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BL600 M
ODULE
W
M
HISPER
ODE
Application Note
I
NTRODUCTION
The goals of this document include the following:
To explain how to use Laird's BL600 module in whisper mode pairing.
To test the Whisper Mode functionality through the use of a BT v4.0-enabled iOS device.
O
VERVIEW
Security is a critical issue in wireless communication. In Bluetooth Low Energy (BLE), when two devices wish
to communicate securely, Simple Secure Pairing is used. This process establishes a secret link key to correctly
authenticate devices. However, in most cases the pairing process itself is carried out on the same exposed
wireless medium and is therefore still vulnerable to interceptions and attacks.
To enhance security and ease during the pairing process, Laird developed a unique approach which involves
the transmission power being significantly decreased while pairing is in progress. This ensures that pairing is
not completed unless the devices are within a relatively close proximity to each other. This behavior is known
as Whisper Mode Pairing. This proximity-enhanced security adds the extra level of trust that can be used to
authenticate BLE devices. An additional benefit of Whisper Mode is that end users of products that are
implementing Laird's BL600 can be certain they are connecting to the correct, intended remote device by
simply bringing them into close proximity. Finally, Laird's whisper mode may decrease footprint and BOM
costs for OEMs by removing requirements for additional wireless technologies, such as Near Field
Communications (NFC); it provides similar attributes from within the BL600 module.
Whisper mode pairing is achieved with the function BleTxPwrWhilePairing(). This function, called once at
startup, sets the transmit power of all packets that are transmitted while pairing is in progress. Radial
measurements have shown that setting the pairing transmit power to -55 creates a 'bubble' with a radius of
about 30 cm, outside which pairing will not succeed. This should be decreased even further if the BL600 is
covered by the final product enclosures which affect the radio's overall RF performance.
R
EQUIREMENTS
PC running Windows XP or later
UWTerminal 6.50 or later
Sample apps as deployed with the firmware's zip file and specifically the application stored in the file
"htss.health.thermometer.sensor.SB"
USB A to mini B cable
BL600 devkit with firmware version 1.5.62.0 or later
iOS device with BT4.0 support (e.g. iPad 3/iPhone 4S/iPad mini or newer)
Internet connection on the iOS device (to download the BL600 app)
Note:
This application note assumes that you are familiar with how to download
onto the BL600 using the UWTerminal utility. If not, refer to the module's user guide and
specifically to the chapter "
Embedded Wireless Solutions Support Center:
https://laird-ews-support.desk.com/?b_id=1945#docs
Embedded Wireless Solutions Support Center:
http://ews-support.lairdtech.com
www.lairdtech.com/bluetooth
Getting Started
". You can access the BL600 user guide from the
1
v1.0
smart
BASIC applications
Americas: +1-800-492-2320
Europe: +44-1628-858-940
Hong Kong: +852 2923 0610
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Table of Contents
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Related Manuals for Laird BL600
Summary of Contents for Laird BL600
- Page 1 -55 creates a ‘bubble’ with a radius of about 30 cm, outside which pairing will not succeed. This should be decreased even further if the BL600 is covered by the final product enclosures which affect the radio’s overall RF performance.
- Page 2 Navigate to the end of the file, and add the line rc = BleTxPwrWhilePairing(-55) before the WaitEvent statement (line 341). This function sets the transmitted power to -55 dBm during pairing. smart Save the BASIC application and load it into the BL600 using UWTerminal. OnStartup() rc=StartAds(ADV_IND) rc=BleTxPwrWhilePairing(-55) '//------------------------------------------------------------------------- '// Wait for a synchronous event.
- Page 3 Notice that even though a connection occurs (Figure 4), no results display on the iOS device’s screen; this indicates that it has not paired to the BL600 module. Figure 4: UWTerminal updated to show that a connection has occurred Embedded Wireless Solutions Support Center:...
- Page 4 5). This does not occur unless the devices are a few inches apart. When you press Pair on the iOS device, the screen updates to show the temperature reading sent by the BL600 module. Figure 5: The iOS device indicating the pairing process is achieved in close proximity...
- Page 5 BL600 Whisper Mode Application Note EVISION ISTORY Revision Date Description Approved By 08 Jan 2015 Initial Release Jonathan Kaye Embedded Wireless Solutions Support Center: Americas: +1-800-492-2320 Europe: +44-1628-858-940 http://ews-support.lairdtech.com Hong Kong: +852 2923 0610 www.lairdtech.com/bluetooth...
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