Quote from: mamuu on February 07, 2024, 08:44:58 PM

Hello there

"R = E.lift_x(r)"
there are 2 possibilities in this line for point R
"R" or "-R"

If "public_key" is not a string but a "point" object(like G) with "E" element (Ellipric Curve)

"R= u2*public_key + u1*G"

it's the right thing to do.

Thank you.

So you are saying i should instead write it like this?

Code:

def verify(r, s, z, public_key, k):
# Compute modular inverse of s
w = modinv(s, n)

# Compute u1 and u2
u1 = z * w % n
u2 = r * w % n

# Compute R using the provided x-coordinate r
R = E.lift_x(r)

# Compute the candidate public key using the provided k value
candidate_public_key = u1 * public_key + u2 * G

# Check if the x-coordinate of the computed R matches that of the candidate public key
if R[0] == candidate_public_key[0]:
print("Signature matches")
return True
else:
print("Invalid signature")
return False