def get_subnode(node, i):
# Public Child key derivation (CKD) algorithm of BIP32
i_as_bytes = struct.pack(">L", i)
if is_prime(i):
raise Exception("Prime derivation not supported")
# Public derivation
data = node.public_key + i_as_bytes
I64 = hmac.HMAC(key=node.chain_code, msg=data,
digestmod=hashlib.sha512).digest()
I_left_as_exponent = string_to_number(I64[:32])
node_out = proto_types.HDNodeType()
node_out.depth = node.depth + 1
node_out.child_num = i
node_out.chain_code = I64[32:]
node_out.fingerprint = fingerprint(node.public_key)
# BIP32 magic converts old public key to new public point
x, y = sec_to_public_pair(node.public_key)
point = I_left_as_exponent * SECP256k1.generator + \
Point(SECP256k1.curve, x, y, SECP256k1.order)
if point == INFINITY:
raise Exception("Point cannot be INFINITY")
# Convert public point to compressed public key
node_out.public_key = point_to_pubkey(point)
return node_out
def public_ckd(public_node, n):
if not isinstance(n, list):
raise Exception('Parameter must be a list')
node = proto_types.HDNodeType()
node.CopyFrom(public_node)
for i in n:
node.CopyFrom(get_subnode(node, i))
return node
def load_device_by_xprv(self, xprv, pin, passphrase_protection, label,
language):
if self.features.initialized:
raise Exception(
"Device is initialized already. Call wipe_device() and try again."
)
if xprv[0:4] not in ('xprv', 'tprv'):
raise Exception("Unknown type of xprv")
if len(xprv) < 100 and len(xprv) > 112:
raise Exception("Invalid length of xprv")
node = types.HDNodeType()
data = tools.b58decode(xprv, None).encode('hex')
if data[90:92] != '00':
raise Exception("Contain invalid private key")
checksum = hashlib.sha256(
hashlib.sha256(binascii.unhexlify(
data[:156])).digest()).hexdigest()[:8]
if checksum != data[156:]:
raise Exception("Checksum doesn't match")
# version 0488ade4
# depth 00
# fingerprint 00000000
# child_num 00000000
# chaincode 873dff81c02f525623fd1fe5167eac3a55a049de3d314bb42ee227ffed37d508
# privkey 00e8f32e723decf4051aefac8e2c93c9c5b214313817cdb01a1494b917c8436b35
# checksum e77e9d71
node.depth = int(data[8:10], 16)
node.fingerprint = int(data[10:18], 16)
node.child_num = int(data[18:26], 16)
node.chain_code = data[26:90].decode('hex')
node.private_key = data[92:156].decode(
'hex') # skip 0x00 indicating privkey
resp = self.call(
proto.LoadDevice(node=node,
pin=pin,
passphrase_protection=passphrase_protection,
language=language,
label=label))
self.init_device()
return resp
def deserialize(xpub):
data = tools.b58decode(xpub, None)
if tools.Hash(data[:-4])[:4] != data[-4:]:
raise Exception("Checksum failed")
node = proto_types.HDNodeType()
node.depth = struct.unpack('>B', data[4:5])[0]
node.fingerprint = struct.unpack('>I', data[5:9])[0]
node.child_num = struct.unpack('>I', data[9:13])[0]
node.chain_code = data[13:45]
key = data[45:-4]
if key[0] == '\x00':
node.private_key = key[1:]
else:
node.public_key = key
return node