Teach you how to grab ZigBee packets through cc2531 and parse encrypted ZigBee packets

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Preface

Long time no see , How was your holiday ？

Recently I've been studying Zigbee , Used EFR32（ Buy links ） Development board , I've studied a little before , I wrote several articles , But I didn't understand and use . lately arduino Tired of playing , I began to go back and continue to study Zigbee , Here's a recommendation Video tutorial of core technology （ Video link ） Well done , But in the process of learning , I have a problem ： I don't know why Simplicity studio I can't use my own bag grabbing tool , It's hard not to grab the bag . So I studied how to catch zigbee package .

however Simplicity studio Although there is little information about the platform , It's a little complicated. , But it's really easy to use after familiarity , Than IAR What's more convenient .

Preparation stage

We need a CC2531 Protocol Analyzer , It also needs to be installed Wireshark （ I used it here 2.4.10 edition , It is said that only 2.4.x edition ）, and TiWsPc .

It should be noted that Wireshark and TiWsPc Must be installed in the default path , And you must install Wireshark After the installation TiWsPc , After the installation is complete Wireshark Add... After the shortcut of ：

Space -i\.\pipe\tiwspc_data -k // Be careful ！ Space is very important ！

When using, you need to open TiWsPc Then open the Wireshark ！

Use steps

TiWsPc

open TiWsPc Click and tick... In order , The corresponding button , When finished, it will look like the one shown in the figure above .
Be careful ：4 The number box is the location of the selected channel , I don't know which channel it is. I need to try one by one , See which channel can catch the packet .

Wireshark

Complete the above layout , open TiWsPc after , Click on the one we modified before Wireshark Shortcut to , The interface for selecting network card will be skipped , Directly enter the packet capture interface ：

But our zigbee It's encrypted. , So we can't interpret the bag we caught at this time , Need configuration Link Key.

Analytic message

stay Wireshark Press the shortcut key ：Ctrl+Shift+P Open the preferences window , Find... In the menu on the left Protocols The drop-down menu , Find... At the bottom Zigbee, And then click Edit Button , add to Link Key：

Here are some commonly used Link Key：

# This file is automatically generated, DO NOT MODIFY.
"5A6967426565416C6C69616E63653039","Normal",""
"821fd8fd9e8b54497ab7905516a38c21","Normal",""
"9b24d9cac760e566b35cb1c25f183dde","Normal",""
"c4f96ae7000506d3fcd1627fb85d7eeb","Normal",""
"aa27404546133c11a2bff89dbe2b74e9","Normal",""
"1770b5f6036c8152af280d6e1ba4594a","Normal",""
"27404546133c11a2bff89dbe2b74e99a","Normal",""
"6bb429da97f0357683ec01d22fa88dee","Normal",""
"691ad73075b6c32c41126fe8cd2edb64","Normal",""
"7d1e0bd4c9fa3710d596230ca1f2cfc8","Normal",""
"2aa7c0c5c693bc91223f781d3eabf469","Normal",""
"e4998a8720a526731c71821fd8fd9e8b","Normal",""
"d73075b6c32c41126fe8cd2edb64190a","Normal",""

Zigbee The encryption

Here we add Link Key, however Zigbee There is also a layer of encryption at the network layer NWK Key .

That's to say Zigbee encryption .Zigbee Respectively in APS Layer and network layer are encrypted , That is to say, corresponding to Link Key and NWK Key.

NWK Key Hop by hop transmission mode , Every device should know the same NWK Key,ZigBee Most communication data are used NWK Key encryption , and NWK Key It was created by ZC Nodes are randomly generated , And the acquisition of newly added devices NWK Key The message is through Link Key Encrypted , Because the device is not connected to the network at this time .

Link Key It's end-to-end transmission , Only the sender and receiver know key, Midway equipment does not need to know , There is no need to decrypt . This Link Key Most of the time it is used to transmit NWK Key , That means we know Link Key After that, it can be carried when accessing the network through the grasping device NWK Key My bag , And then know NWK Key .

This seemingly troublesome process Wireshark It can automatically help us complete ,Wireshark Added Link Key after , Capture the network access process of a device , be Wireshark It will automatically parse the... From the process of accessing the network Zigbee Online NWK KEY.

summary

Wireshark The first day ！ I was still struggling to figure out how to catch it NWK Key My bag , And found that Wireshark It's done automatically ！ It's so strong ！