nRF9160DK ECDSA non-deterministic

[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), so we can send our information to an Ethereum Blockchain. We discovered that ECDSA non-deterministic algorithm is not so accurate. There is the possibility that the sign of ECDSA is not correct on the first attempt, but we need to execute our application more times.
Thank you all!

[dejans]

Hi,

We discovered that ECDSA non-deterministic algorithm is not so accurate.

Could you describe the procedure how you determined that the algorithm is not so accurate? In which way is it not so accurate?

There is the possibility that the sign of ECDSA is not correct on the first attempt, but we need to execute our application more times.

Could you elaborate on this?

Best regards,
Dejan

[Gioele]

Okay, now I will try to explain all the procedures.
Like I said we need to create a raw transaction for an Ethereum Blockchain.
To create the raw transaction we need to follow some steps:
1)Make the RLP of the information
2)Make the Keccack256 of the RLP above
3)Make the ECDSA of the Keccack256 resulting
4)Make another time the RLP of the information plus the values of the sign of the ECDSA

We make this procedure for any time we need to create a transaction.
We use ECDSA non-deterministic so the values of the sign are different every time. We are mathematically sure of the whole procedure, the only thing that we can't be sure of is the ECDSA. Sometimes the raw transaction is correct the first time, sometimes we need to repeat the procedure to obtain different sign values because not always the raw transaction is considered valid. The problem is related to the ECDSA.

[dejans]

Hi,

Which criteria did you use to determine the validity of the raw transaction?

Best regards,
Dejan

[Gioele]

I send the transaction to the Blockchain, or I just use a transaction decoder. These methods show me if the transaction is correct or not.

[dejans]

Hi,

I have made an internal inquiry related to your question.
We are planning to perform some tests. Please note that this may take at least several days. I'll get back to you when I get new information.

Best regards,
Dejan