def serialize_xpub(k):
b = b''
b += HD_HEADER_PUBLIC
b += convert.int_to_byte(k['depth'])
b += k['fingerprint']
b += convert.int_to_bytes(k['i'], 4)
b += k['chaincode']
b += ecdsa.serialize_pub(k['pub'])
return convert.bytes_to_b58check(b)
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 derive_xpriv(k, i):
i = int(i)
pub = ecdsa.priv_to_pub(k['priv'])
pub_ser = ecdsa.serialize_pub(pub)
priv_ser = ecdsa.serialize_priv(k['priv'])
if i >= 2**31:
hmacdata = b'\x00' + priv_ser + convert.int_to_bytes(i, 4)
else:
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:],
'priv': ec.add_scalar(k['priv'], ecdsa.deserialize_priv(I[:32]))
}
def test_serialize(self):
for _ in range(10):
priv = ecdsa.random_priv()
pub = ecdsa.priv_to_pub(priv)
self.assertEqual(pub, ecdsa.deserialize_pub(ecdsa.serialize_pub(pub, compressed=False)))
self.assertEqual(pub, ecdsa.deserialize_pub(ecdsa.serialize_pub(pub, compressed=True)))