RE: sniffer does not decrypt packets after pairing

Karl Ylvisaker — Thu, 03 Sep 2020 11:49:48 GMT

Hello,

[quote user=""]I can't see the packet content after encryption is started.[/quote][quote user=""]DLE packets was not decrypted correctly[/quote]

By this, do you mean that you do in fact see the packets - but not their contents? The message "packet was not decrypted correctly(bad MIC)" is most commonly caused by the sniffer not having the private keys for the connection, so it can not decrypt the packages it intercepts.
To ensure that the sniffer gets the keys, it will need to be sniffing for the particular device at the time of pairing / bonding.
I.e you will need to select your device from the device menu ( shown in the included picture ) before going into the secure connection. This will let the sniffer acquire the keys, and follow into the connection.
In the case that your devices are already bonded ( the keys are stored on the devices ) then you will need to delete the bonds before pairing / bonding again, to ensure that the sniffer is present during the key exchange.
Please try this and let me know if this lets you see the packets' content.

Additionally, out of curiosity, could you tell me which device you are pairing your nRF52840 with? Is it a iOS / Android smartphone, or nRF Connect application for desktop?

Best regards,
Karl