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trezor-firmware/tests/bip32.py

148 lines
4.5 KiB
Python

# This file is part of the Trezor project.
#
# Copyright (C) 2012-2019 SatoshiLabs and contributors
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the License along with this library.
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
import hashlib
import hmac
import struct
from copy import copy
from typing import Any, List, Tuple
import ecdsa
from ecdsa.curves import SECP256k1
from ecdsa.ellipticcurve import INFINITY, Point
from ecdsa.util import number_to_string, string_to_number
from trezorlib import messages, tools
def point_to_pubkey(point: Point) -> bytes:
order = SECP256k1.order
x_str = number_to_string(point.x(), order)
y_str = number_to_string(point.y(), order)
vk = x_str + y_str
return struct.pack("B", (vk[63] & 1) + 2) + vk[0:32] # To compressed key
def sec_to_public_pair(pubkey: bytes) -> Tuple[int, Any]:
"""Convert a public key in sec binary format to a public pair."""
x = string_to_number(pubkey[1:33])
sec0 = pubkey[:1]
if sec0 not in (b"\2", b"\3"):
raise ValueError("Compressed pubkey expected")
def public_pair_for_x(generator, x: int, is_even: bool) -> Tuple[int, Any]:
curve = generator.curve()
p = curve.p()
alpha = (pow(x, 3, p) + curve.a() * x + curve.b()) % p
beta = ecdsa.numbertheory.square_root_mod_prime(alpha, p)
if is_even == bool(beta & 1):
return (x, p - beta)
return (x, beta)
return public_pair_for_x(
ecdsa.ecdsa.generator_secp256k1, x, is_even=(sec0 == b"\2")
)
def fingerprint(pubkey: bytes) -> int:
return string_to_number(tools.hash_160(pubkey)[:4])
def get_address(public_node: messages.HDNodeType, address_type: int) -> str:
return tools.public_key_to_bc_address(public_node.public_key, address_type)
def public_ckd(public_node: messages.HDNodeType, n: List[int]):
if not isinstance(n, list):
raise ValueError("Parameter must be a list")
node = copy(public_node)
for i in n:
node = get_subnode(node, i)
return node
def get_subnode(node: messages.HDNodeType, i: int) -> messages.HDNodeType:
# Public Child key derivation (CKD) algorithm of BIP32
i_as_bytes = struct.pack(">L", i)
if i & tools.HARDENED_FLAG:
raise ValueError("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])
# 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 ValueError("Point cannot be INFINITY")
return messages.HDNodeType(
depth=node.depth + 1,
child_num=i,
chain_code=I64[32:],
fingerprint=fingerprint(node.public_key),
# Convert public point to compressed public key
public_key=point_to_pubkey(point),
)
def serialize(node: messages.HDNodeType, version: int = 0x0488B21E) -> str:
s = b""
s += struct.pack(">I", version)
s += struct.pack(">B", node.depth)
s += struct.pack(">I", node.fingerprint)
s += struct.pack(">I", node.child_num)
s += node.chain_code
if node.private_key:
s += b"\x00" + node.private_key
else:
s += node.public_key
s += tools.btc_hash(s)[:4]
return tools.b58encode(s)
def deserialize(xpub: str) -> messages.HDNodeType:
data = tools.b58decode(xpub, None)
if tools.btc_hash(data[:-4])[:4] != data[-4:]:
raise ValueError("Checksum failed")
node = messages.HDNodeType(
depth=struct.unpack(">B", data[4:5])[0],
fingerprint=struct.unpack(">I", data[5:9])[0],
child_num=struct.unpack(">I", data[9:13])[0],
chain_code=data[13:45],
public_key=None,
)
key = data[45:-4]
if key[0] == 0:
node.private_key = key[1:]
else:
node.public_key = key
return node