Figure 8 - BPA 600 datasource
Encryption Key Entry
a.
Passkey Entry
is easiest if you have the code that was
displayed or entered during device pairing. The code is
what is used to generate the LTK. Under
LE
Encryption
enter the code in the
Enter New
PIN/OOB
data text box.
b.
Just Works
is more of a challenge because you must
know the LTK that is created at the time of pairing and
identification of an encrypted link.
l
If your device was previously used in an encrypted
capture session, the device information including
LTK can be found in the
Device Database
tab.
l
In a design and development environment the LTK is
often known beforehand.
l
Capture of Host Controller Interface (HCI) events using ComProbe HSU can reveal the LTK,
which is contained in the HCI_Link_Key_Request_Reply command. HCI capture is through
direct connection to the device host controller. The information obtained in a direct
connection can later be used in a wireless encrypted capture session that requires prior
knowledge of encryption keys.
5. To start capture click on the Start Sniffing button
on the
BPA 600 datasource
toolbar.
A.1.7.2 Use Frame Display to View Encryption/Decryption Process
A.1.7.2.1 Security Manager Protocol
The Security Manager Protocol (SMP) controls the process for pairing and key distribution. The results of a
pairing and key distribution can be observed in the ComProbe software
Frame Display
. Activate the
Frame
Display
by clicking on the icon on the
Control
window toolbar. On the
Frame Display
low energy protocols
are shown in light green tabs. Click on the
SMP
protocol tab that will show only the SMP commands from the
full data set.
Figure 9 - SMP Pairing Request (Frame# 35,539) from Initiator (Side 1)
On the left side of the figure above is the
Frame Display Decode
r pane that shows the decoded
information supplied in the selected frame in the Summary pane, Frame# 35,539. Shown is the SMP data
associated with and encrypted link (MITM Protection = Yes). The requested keys are also shown. Selecting
Frame# 35,545 would provide the response from the responder (Side 2) and would contain similar
information.
Appendicies
TELEDYNE LECROY
Frontline BPA low energy Hardware & Software User Manual
200
Summary of Contents for BPA LOW ENERGY
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