def child(self, i: int) -> 'Xprv':
hardened = i >= 1 << 31
if hardened:
I = hmac.new(key=self.code,
msg=self.keydata() +
int_to_bytes(i).rjust(4, b'\x00'),
digestmod=hashlib.sha512).digest()
tmp = int_to_bytes(i).rjust(4, b'\x00')
else:
I = hmac.new(key=self.code,
msg=self.key.to_public().encode(compressed=True) +
int_to_bytes(i).rjust(4, b'\x00'),
digestmod=hashlib.sha512).digest()
tmp = self.key.to_public().encode(
compressed=True) + int_to_bytes(i).rjust(4, b'\x00')
I_L, I_R = bytes_to_int(I[:32]), I[32:]
key = (I_L + self.key.int()) % CURVE.order
if I_L >= CURVE.order or key == 0:
return self.child(i + 1)
ret_code = I_R
if hardened:
path = self.path + f'/{i - 2 ** 31}h'
else:
path = self.path + f'/{i}'
return Xprv(WitPrivateKey.from_int(key),
ret_code,
depth=self.depth + 1,
i=i,
parent=self.fingerprint(),
path=path)
def child(self, i: int) -> 'Xpub':
hardened = i >= 1 << 31
if hardened:
raise KeyDerivationError(
'Cannot derive a hardened key from an extended public key')
I = hmac.new(key=self.code,
msg=self.keydata() + int_to_bytes(i).rjust(4, b'\x00'),
digestmod=hashlib.sha512).digest()
tmp = bytes_to_hex(self.keydata() + int_to_bytes(i).rjust(4, b'\x00'))
I_L, I_R = I[:32], I[32:]
key = WitPrivateKey(I_L).to_public().point + self.key.point
ret_code = I_R
path = self.path + f'/{i}'
# TODO add point at infinity check
return Xpub(WitPublicKey(key),
ret_code,
depth=self.depth + 1,
i=i,
parent=self.fingerprint(),
path=path)
def pub_key(self):
if self.y & 1: # odd root
return PublicKey(_bytes=int_to_bytes(self.x).rjust(32, b'\x00'),
compressed=3)
else: # even root
return PublicKey(_bytes=int_to_bytes(self.x).rjust(32, b'\x00'),
compressed=2)
def encode(self, compressed=True) -> bytes:
if compressed:
if self.y & 1: # odd root
return b'\x03' + int_to_bytes(self.x).rjust(32, b'\x00')
else: # even root
return b'\x02' + int_to_bytes(self.x).rjust(32, b'\x00')
return b'\x04' + int_to_bytes(self.x).rjust(
32, b'\x00') + int_to_bytes(self.y).rjust(32, b'\x00')
def encode(self, compact=False):
"""https://github.com/bitcoin/bips/blob/master/bip-0062.mediawiki#der-encoding"""
r = int_to_bytes(self.r)
if r[0] > 0x7f:
r = b'\x00' + r
s = int_to_bytes(self.s)
if s[0] > 0x7f:
s = b'\x00' + s
len_r = int_to_bytes(len(r))
len_s = int_to_bytes(len(s))
len_sig = int_to_bytes(len(r) + len(s) + 4)
if compact:
return r + s
return b'\x30' + len_sig + b'\x02' + len_r + r + b'\x02' + len_s + s
def decode(b58: str) -> bytes:
partial_sum = 0
exponent = 0
for digit in reversed(b58):
try:
partial_sum += ALPHABET.index(digit) * BASE**exponent
except ValueError:
raise Base58DecodeError('Bad Byte') from None
exponent += 1
return int_to_bytes(partial_sum)
def from_binary(cls, b):
return cls(int_to_bytes(int(b, 2)))
def from_int(cls, i):
return cls(int_to_bytes(i))
def from_json(cls, data: dict):
_bytes, _compressed = data.values()
return WitPublicKey.from_hex(
bytes_to_hex((int_to_bytes(_compressed) +
bytes(_bytes).rjust(32, b'\x00'))))
def pb_bytes(self) -> bytes:
return pb_field(field_number=1,
tag=LENGTH_DELIMITED,
value=concat(
[int_to_bytes(self.compressed), self._bytes]))