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 derive_xpub(k, i):
i = int(i)
if i >= 2**31:
raise Exception("Can't do private derivation on public key!")
pub = k['pub']
pub_ser = ecdsa.serialize_pub(pub)
hmacdata = pub_ser + convert.int_to_bytes(i, 4)
I = hmac.new(k['chaincode'], hmacdata, hashlib.sha512).digest()
return {
'depth': k['depth'] + 1,
'fingerprint': hashes.hash160(pub_ser)[:4],
'i': i,
'chaincode': I[32:],
'pub': ec.add(k['pub'], ecdsa.priv_to_pub(ecdsa.deserialize_priv(I[:32])))
}
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])