ValueError when multiplying the generator with the order of the curve

[ghost]

Multiplying the generator with the order of the curve gives a ValueError:

$ python -c 'from fastecdsa.curve import secp256k1; secp256k1.q * secp256k1.G'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/bbralf/brainbot-com/venv/lib64/python3.8/site-packages/fastecdsa/point.py", line 163, in __rmul__
    return self.__mul__(scalar)
  File "/home/bbralf/brainbot-com/venv/lib64/python3.8/site-packages/fastecdsa/point.py", line 150, in __mul__
    return Point(int(x), int(y), self.curve)
  File "/home/bbralf/brainbot-com/venv/lib64/python3.8/site-packages/fastecdsa/point.py", line 33, in __init__
    raise ValueError(
ValueError: coordinates are not on curve <secp256k1>
        x=0
        y=0

[AntonKueltz]

Good catch, v2.1.2 broke this when it fixed the C extension's handling of the point at infinity. (The joys of Weierstrass curves, this is why the Montgomery curves like Curve25519 are better for implementors and more resistant to side channels). Fixed in commit a591b79 (version v2.1.3).

➜  ~ pip install fastecdsa==2.1.3
Collecting fastecdsa==2.1.3
  Using cached fastecdsa-2.1.3-cp38-cp38-macosx_10_14_x86_64.whl (53 kB)
Installing collected packages: fastecdsa
Successfully installed fastecdsa-2.1.3
➜  ~ python -c 'from fastecdsa.curve import secp256k1; secp256k1.q * secp256k1.G'
➜  ~

[ghost]

Thanks!