Hi @C141FE,
This is what Silicon Labs says about the Application link key:
Standard security supports devices establishing application link keys with other devices. These keys are separate from the trust center link key and not required for normal operation.
And this is what they say about the Installation code:
An installation code key is just a preconfigured trust center link key used to enter the Zigbee network and obtain the current network key. Because this unique key must be known to both the joining device and the trust center at the time of network entry, a piece of shareable data known as the “installation code” (sometimes also referred to as the “install code”) is used to derive the key at both sides.
The code can be any arbitrary value of 6, 8, 12, or 16 bytes, followed by a 16-bit CRC (least significant byte first) over those bytes.
Find more information at https://www.silabs.com/documents/public/application-notes/an1233-zigbee-security.pdf. It seems like the logs show the Installation code key (or Trust center link key) but not the Installation code (or Install code). I’m still trying to find this value. I also think Oleg may be able to give us more information about it.