When recovering the public key from ECDSA signature (r, s), the first step is recovering the point R.
You do this by plugging in (r + xn) into the curve equation where n is the order of the basepoint and x is some integer
my question is how do you find this x value, say for secp256k1 but also the general case
I have a vauge notion that this may be related to the cofactor of the curve (usually working with secp256k1 this shouldnt be important). But im failing to find more info on it.