SBSFU - ECCKEY and AES Key

[STsch.1]

Hi,

I have a bit trouble understanding the two keys in the SBSFU and which pairs is actually used. From AN5056, chapter 5 there is stated how to generate the two different methods and the AES key I could successfully adjust. With the ECCKEY method and when I adjust the key (I used the following generator: https://8gwifi.org/sshfunctions.jsp) I am not able to run the prebuild.sh anymore successful.

I get the following error when running the prebuild.sh with a different key than the original in the examples:

So the key is somehow not the correct one. So my questions are:

1.) Do I need to change both keys (the OEM keys in the .bin for AES and the ECCKEY1)?

2.) Is there a generator for the ECCKEY1 key?

[Jocelyn RICARD]

Hello @STsch.1​ ,

I would suggest using either openssl or our prepareimage tool to generate those keys.

The AES key is anyway a pure random value.

The ECC Key should be generated in a PEM format.

For prepareimage tool, please have a look to

STM32CubeExpansion_SBSFU_V2.6.0\Middlewares\ST\STM32_Secure_Engine\Utilities\KeysAndImages\readme.txt

You should find what you need

Best regards

Jocelyn