RE: OpenThread master key usage and generation

zhliao — Thu, 12 Dec 2019 15:34:14 GMT

Hi Jorgen,

Thanks for your reply! I will let you know if I have any other questions.

Best,

Zhonghao

Jørgen Holmefjord — Wed, 11 Dec 2019 16:34:49 GMT

Hi,

The default master key is hardcoded into the OpenThread libraries. You can set a new key in the application using otThreadSetMasterKey() API call. PAN ID and channel can be configured in the sdk_config.h file of the projects in the SDK, or you can use otLinkSetPanId() in your application to set it.
This is from Thread 1.1.1 specification: "With the exception of in-band commissioning, all messages are secured, either by [IEEE802154] security (level 5, encryption and 32-bit MIC), or by the MLE protocol (which is based on 802.15.4 AES-CCM frame security, but done above the link layer). The 802.15.4 and MLE keys are derived from the master key received during commissioning". As far I know, the UDP packets are not encrypted beyond this unless DTLS is used for end-to-end encryption.
The PSKc is the Pre-Shared Key for the Commissioner, see this guide.
I do not have any experience with using raw public keys, and unfortunately, I'm not aware of any references for this.

Best regards,
Jørgen