# Bitcoin ECDSA signature

I am trying to use the ecdsaSign function in ecdsa.c of https://github.com/kvhnuke/Ethereum-Arduino/tree/master/Ethereum-Arduino/libs which is based on the files in the repo https://github.com/someone42/hardware-bitcoin-wallet

The signature that I generate using the above function ea9c02e96049f6e0ca1ddbcb1ef4ab122ab1d42fb52e537456b446c281cc72342caeec1d88d2ed67d14a06358148468e61a4e5a499cc7972be39e9f46c2cf06a

To crosscheck it I am using the ecdsa_sign function from the repo https://github.com/trezor/trezor-firmware/tree/master/crypto which I know generates the desired signature - f388ade4a3ef1f44ff31e860ca8e92c6d0fa77562b274f59a8b82af3e7c3177a5851f9720efe77b1872e23a2545b71aed5451ed4ff1c0fc2cac093fc084b99d6

msg used : 1020212013102021201310202120131020212013102021201310202120131020

privkey used : 8000238ac88eef15f5dae0c5ec08525f26ebe36a23fb81255a1595098b559c02

• The signature consists of an $(r, s)$ value, usually concatenated. No prices for guessing why the first value is called $r$. – Maarten Bodewes Aug 17 '20 at 21:22