ECDH on atecc508a

Go To Last Post
2 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hello,

 

I'm trying to create a premaster key with the ECDH command on an atecc508a. I am using a device where both the config and data zones are locked, where slot00 was configured for a private ECC p256 key. I've tried both through my own implementation using cryptoauthlib, as well as through the ACES tool (v. 6.0.2.21684)). In both cases, I get 0x0F back.

 

Here's a sample: 

 

ECDH Command Sent:
47 43 00 00 00 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 77 75
EcdhCmd Received:
04 0F 23 42

 

From the config zone:

<SlotConfig00>87 20</SlotConfig00>

and

<KeyConfig00>33 00</KeyConfig00>

 

Any ideas?

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I figured this out. I was sending random bytes as the public key when creating the ECDH PMS, but it really needed to be a non-random public key generated in the device.