Watch lora Packets on Rak831

Hi there,
I’ve a question and probably it’s not related with ttn. I have a RAK831 lora gateway, and my idea is to watch the received lora packets before posting them on the internet. My idea is to read de packets without the necesity of having internet connection, directly on my raspberry, where the RAK831 is mounted.

you can’t decrypt packets , but you can see them

Hi BoRRoZ,
Thanks for replying!
Do you mean I can see that a new packet has arrived but I can’t see its content?

You can decrypt them if they’re yours, you just wouldn’t have the keys to decrypt traffic to anyone else’s nodes unless they shared those with you.

In the case of OTAA nodes in addition to knowing the original secrets you also need to see the join request and response that kicked off the current session, so that you can derive the session keys in use the same way that the node does. If you have enough geographic isolation that the traffic could only have gone through your gateway, that is also fairly simple in practice provided that you were watching / recording when it happened.

Writing the code to actual do this provides an excellent education in the details of how LoRaWan works - and also shines a spotlight on various design decisions that cause it to fail to work very well in some not-uncommon cases.

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