Unable to Decrypt the Friendship Packets between Low Power Node and Friend Node

[Chandu_Maharaj]

Hi,

I am able to sniff  and decrypt all the packets in Mesh Network as per NRF_Sniff Procedure Manual.

But unable to decrypt the packets received between the Low Power Node and Friend Node. As I have gone through Mesh Profile Specification, it is mentioned the security credentials are different for Friendship PDU and Network PDU.

So, what are the necessary changes should i have make to decrypt those packets also.

Devices used for Sniffing are:

nRF52832 DK

nRF52840 DK

nRF52840 Dongle

with given sniffer hex files.

Tool used: Wireshark (as per specfied in nRF_sniffing Procedure Manual)

Thanks in Advance

K Chandu

[Hung Bui]

Hi Chandu, 

We haven't tried to use the nRF Sniffer to decrypt friendship communication (we usually just use the logs on both sides for debugging, instead of sniffing the communication). 

But I would suggest you to have a look at section 3.6.6.2 Friendship security in Mesh Profile specification v1.0.1 for more information about encryption in friendship communication. 

[Chandu_Maharaj]

Thanks Hung,

I have gone through the specification, the security credentials  are different for both Mesh Network and Friendship Network.

The master security material is derived from the master security credentials using:

NID || EncryptionKey || PrivacyKey = k2(NetKey, 0x00)

The friendship security material is derived from the friendship security credentials using:
NID || EncryptionKey || PrivacyKey = k2(NetKey, 0x01 || LPNAddress || FriendAddress ||
LPNCounter || FriendCounter)

Referred from section 3.8.6.3.1

Can u suggest any fields to be updated in Wireshark, to decrypt the data.