def verify(msghash, sig, pub):
assert isinstance(msghash, bytes)
assert isinstance(sig, tuple)
assert isinstance(pub, tuple)
_, r, s = sig
w = ec.inv(s, ec.N)
z = convert.bytes_to_int(msghash)
u1, u2 = z * w % ec.N, r * w % ec.N
x, _ = ec.add(ec.multiply(ec.G, u1), ec.multiply(pub, u2))
return r == x
def sign(msghash, priv):
assert isinstance(msghash, bytes)
assert isinstance(priv, int)
z = convert.bytes_to_int(msghash)
k = deterministic_generate_k(msghash, priv)
r, y = ec.multiply(ec.G, k)
s = ec.inv(k, ec.N) * (z + r * priv) % ec.N
# Ensure Low S constraint against tx malleability
# https://github.com/bitcoin/bips/blob/master/bip-0062.mediawiki#Low_S_values_in_signatures
if s > ec.N // 2:
s = ec.N - s
y += 1 # Switch parity of y, otherwise recover breaks.
return 27 + (y % 2), r, s
def test_all(self):
for _ in range(20):
x, y = random.randrange(2**256), random.randrange(2**256)
self.assertFalse(ec.is_curve_point((x,y)))
G_x = ec.multiply(ec.G, x)
G_y = ec.multiply(ec.G, y)
self.assertTrue(ec.is_curve_point(G_x))
self.assertEqual(
ec.multiply(G_x, y)[0],
ec.multiply(G_y, x)[0]
)
self.assertEqual(
ec.add(G_x, G_y)[0],
ec.multiply(ec.G, ec.add_scalar(x, y))[0]
)
self.assertEqual(
ec.substract(G_x, G_y)[0],
ec.multiply(ec.G, ec.substract_scalar(x, y))[0]
)
self.assertEqual(ec.G[0], ec.multiply(ec.divide(ec.G, x), x)[0])
def priv_to_pub(priv):
assert isinstance(priv, int)
return ec.multiply(ec.G, priv)
