nRF9160 DK Ethereum Ecdsa "s problem"

[Gioele]

Hello!
We are trying to sign our data using ECDSA (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/crypto/ecdsa/README.html). 
We are comparing the results with signs of other projects and we see that our program computes the same sign but we ascertain that our "s" is wrong.
What should we do?
The ECDSA sample doesn't provide the Keccak256 algorithm so we implemented it ourselves. We think that there is a mistake with the procedure to obtain the "s value".
Please help us.

[dejans]

Hi,

Thank you for this information.

I would appreciate it if you could answer following 2 questions.

We think that there is a mistake with the procedure to obtain the "s value".

Could you provide more information about the procedure that you used in both cases?

dejans said:

Gioele said:

This is the correct output that comes from another Python Project:

Gioele said:

This is the output that comes from the ECDSA provided by Nordic.

Could you provide more information about the way in which you calculated the values you provided?

Best regards,
Dejan

[Gioele]

We understood that the problem is related to the ECDSA provided by Nordic that doesn't take in input Keccak256.