FrontLine BPA LOW ENERGY, Hardware User Manual

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A.1.7.3 Viewing Encryption in the Message Sequence Chart
Figure 13 - MSC SMP Paring (BPA 600 low energy capture)
The ComProbe software
Message
Sequence Chart
(
MSC
) links directly
to frames being viewed in the Frame
Display. Similarly MSC will display the
same information as the
Frame
Display Decoder
pane. Frames are
synchronized between the
Frame
Display Summary
pane and the
MSC
, so clicking on a frame in either
window will select that same frame in
the other window. Also the protocol
tabs are the same in each window. To
see the pairing process, click on the
SMP tab.
In the image above we see Frame#
35,539 initiating the pairing from the
master device. The response, SMP_
Pairing Response, is sent from the slave
in Frame# 35,545. SMP_Pairing
Confirm occurs between the master and the slave devices at Frame# 39,591 and 39,600 respectively.
Clicking on the MSC LE LL tab will show the process of encrypting a session link. Clicking on Frame# 39,617
displays the LL_ENC_REQ command from the master to the slave. In the MSC below this command you will
see the data transferred that includes SKD
master
used to generate the LTK. At Frame# 39,623 the slave
responds with LL_ENC_RSP sending SKD
slave
to generate LTK at the master. Up to this point all transmissions
are unencrypted. For this example the slave sends the request to start encryption, LL_START_ENC_REQ, at
Frame#39,635. The master responds with LL_START_ENC_RSP at Frame# 39,639, and finally the slave
responds with LL_START_ENC_RSP at Frame# 36,649. At this point the session link is encrypted.
Figure 14 - MSC link Layer Encryption (BPA 600 low energy capture)
A.1.7.4 Viewing Decrypted Data
In the ComProbe software Frame Display click on the LE BB tab. Search in the Summary pane for
Decryption Initiated = Yes frames. In the example depicted in the following figure, Frame# 39723 is selected.
In the
Decoder pane LE BB shows that the decryption was initiated and decryption was successful. In LE Data
Appendicies TELEDYNE LECROY
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