def test_encode(self):
"""Unit test native Python EC point encoding"""
G, _ = get_ec_curve_params(b'nistp256')
with self.subTest('Encode infinity'):
self.assertEqual(encode_ec_point(None, None, None), b'\x00')
with self.subTest('Decode infinity'):
point = PrimePoint.decode(G.curve, b'\x00')
self.assertEqual((point.curve, point.x, point.y),
(None, None, None))
with self.subTest('Encode and decode'):
self.assertEqual(PrimePoint.decode(G.curve, G.encode()), G)
with self.subTest('Bad point type'):
with self.assertRaises(ValueError):
decode_ec_point(0, b'\x05')
with self.subTest('Bad point length'):
with self.assertRaises(ValueError):
decode_ec_point(G.curve.keylen, G.encode()[:-1])
def test_math(self):
"""Unit test native Python EC point math"""
G, n = get_ec_curve_params(b'nistp256')
G2, _ = get_ec_curve_params(b'nistp521')
Inf = PrimePoint.construct(G.curve, None, None)
with self.subTest('Add to infinity'):
self.assertEqual(G + Inf, G)
with self.subTest('Negate'):
negG = -G
self.assertEqual(-negG, G)
with self.subTest('Negate infinity'):
self.assertEqual(-Inf, Inf)
with self.subTest('Multiply returning infinity'):
self.assertEqual(n * G, Inf)
with self.subTest('Add from different curves'):
with self.assertRaises(ValueError):
_ = G + G2