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electrum-bitcoinprivate
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electrum-bitcoinprivate/lib/bitcoin.py

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# -*- coding: utf-8 -*-
#
# Electrum - lightweight bitcoinprivate client
# Copyright (C) 2011 thomasv@gitorious
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import hashlib
import base64
import hmac
import os
import json
import ecdsa
import pyaes
from .util import bfh, bh2u, to_string, BitcoinException
from . import version
from .util import print_error, InvalidPassword, assert_bytes, to_bytes, inv_dict
from . import constants
################################## transactions
COINBASE_MATURITY = 100
COIN = 100000000
# supported types of transaction outputs
TYPE_ADDRESS = 0
TYPE_PUBKEY = 1
TYPE_SCRIPT = 2
# AES encryption
try:
from Cryptodome.Cipher import AES
except:
AES = None
class InvalidPadding(Exception):
pass
def append_PKCS7_padding(data):
assert_bytes(data)
padlen = 16 - (len(data) % 16)
return data + bytes([padlen]) * padlen
def strip_PKCS7_padding(data):
assert_bytes(data)
if len(data) % 16 != 0 or len(data) == 0:
raise InvalidPadding("invalid length")
padlen = data[-1]
if padlen > 16:
raise InvalidPadding("invalid padding byte (large)")
for i in data[-padlen:]:
if i != padlen:
raise InvalidPadding("invalid padding byte (inconsistent)")
return data[0:-padlen]
def aes_encrypt_with_iv(key, iv, data):
assert_bytes(key, iv, data)
data = append_PKCS7_padding(data)
if AES:
e = AES.new(key, AES.MODE_CBC, iv).encrypt(data)
else:
aes_cbc = pyaes.AESModeOfOperationCBC(key, iv=iv)
aes = pyaes.Encrypter(aes_cbc, padding=pyaes.PADDING_NONE)
e = aes.feed(data) + aes.feed() # empty aes.feed() flushes buffer
return e
def aes_decrypt_with_iv(key, iv, data):
assert_bytes(key, iv, data)
if AES:
cipher = AES.new(key, AES.MODE_CBC, iv)
data = cipher.decrypt(data)
else:
aes_cbc = pyaes.AESModeOfOperationCBC(key, iv=iv)
aes = pyaes.Decrypter(aes_cbc, padding=pyaes.PADDING_NONE)
data = aes.feed(data) + aes.feed() # empty aes.feed() flushes buffer
try:
return strip_PKCS7_padding(data)
except InvalidPadding:
raise InvalidPassword()
def EncodeAES(secret, s):
assert_bytes(s)
iv = bytes(os.urandom(16))
ct = aes_encrypt_with_iv(secret, iv, s)
e = iv + ct
return base64.b64encode(e)
def DecodeAES(secret, e):
e = bytes(base64.b64decode(e))
iv, e = e[:16], e[16:]
s = aes_decrypt_with_iv(secret, iv, e)
return s
def pw_encode(s, password):
if password:
secret = Hash(password)
return EncodeAES(secret, to_bytes(s, "utf8")).decode('utf8')
else:
return s
def pw_decode(s, password):
if password is not None:
secret = Hash(password)
try:
d = to_string(DecodeAES(secret, s), "utf8")
except Exception:
raise InvalidPassword()
return d
else:
return s
def rev_hex(s):
return bh2u(bfh(s)[::-1])
def int_to_hex(i, length=1):
if not isinstance(i, int):
raise TypeError('{} instead of int'.format(i))
if i < 0:
# two's complement
i = pow(256, length) + i
s = hex(i)[2:].rstrip('L')
s = "0"*(2*length - len(s)) + s
return rev_hex(s)
def var_int(i):
# https://en.bitcoin.it/wiki/Protocol_specification#Variable_length_integer
if i<0xfd:
return int_to_hex(i)
elif i<=0xffff:
return "fd"+int_to_hex(i,2)
elif i<=0xffffffff:
return "fe"+int_to_hex(i,4)
else:
return "ff"+int_to_hex(i,8)
def op_push(i):
if i<0x4c: # OP_PUSHDATA1
return int_to_hex(i)
elif i<=0xff:
return '4c' + int_to_hex(i)
elif i<=0xffff:
return '4d' + int_to_hex(i,2)
else:
return '4e' + int_to_hex(i,4)
def push_script(x):
return op_push(len(x)//2) + x
def sha256(x):
x = to_bytes(x, 'utf8')
return bytes(hashlib.sha256(x).digest())
def Hash(x):
x = to_bytes(x, 'utf8')
out = bytes(sha256(sha256(x)))
return out
hash_encode = lambda x: bh2u(x[::-1])
hash_decode = lambda x: bfh(x)[::-1]
hmac_sha_512 = lambda x, y: hmac.new(x, y, hashlib.sha512).digest()
def is_new_seed(x, prefix=version.SEED_PREFIX):
from . import mnemonic
x = mnemonic.normalize_text(x)
s = bh2u(hmac_sha_512(b"Seed version", x.encode('utf8')))
return s.startswith(prefix)
def is_old_seed(seed):
from . import old_mnemonic, mnemonic
seed = mnemonic.normalize_text(seed)
words = seed.split()
try:
# checks here are deliberately left weak for legacy reasons, see #3149
old_mnemonic.mn_decode(words)
uses_electrum_words = True
except Exception:
uses_electrum_words = False
try:
seed = bfh(seed)
is_hex = (len(seed) == 16 or len(seed) == 32)
except Exception:
is_hex = False
return is_hex or (uses_electrum_words and (len(words) == 12 or len(words) == 24))
def seed_type(x):
if is_old_seed(x):
return 'old'
elif is_new_seed(x):
return 'standard'
return ''
is_seed = lambda x: bool(seed_type(x))
# pywallet openssl private key implementation
def i2o_ECPublicKey(pubkey, compressed=False):
# public keys are 65 bytes long (520 bits)
# 0x04 + 32-byte X-coordinate + 32-byte Y-coordinate
# 0x00 = point at infinity, 0x02 and 0x03 = compressed, 0x04 = uncompressed
# compressed keys: <sign> <x> where <sign> is 0x02 if y is even and 0x03 if y is odd
if compressed:
if pubkey.point.y() & 1:
key = '03' + '%064x' % pubkey.point.x()
else:
key = '02' + '%064x' % pubkey.point.x()
else:
key = '04' + \
'%064x' % pubkey.point.x() + \
'%064x' % pubkey.point.y()
return bfh(key)
# end pywallet openssl private key implementation
############ functions from pywallet #####################
def hash_160(public_key):
try:
md = hashlib.new('ripemd160')
md.update(sha256(public_key))
return md.digest()
except BaseException:
from . import ripemd
md = ripemd.new(sha256(public_key))
return md.digest()
def hash160_to_b58_address(h160, addrtype):
s = addrtype
s += h160
return base_encode(s+Hash(s)[0:4], base=58)
def b58_address_to_hash160(addr):
addr = to_bytes(addr, 'ascii')
_bytes = base_decode(addr, 26, base=58)
return _bytes[0:2], _bytes[2:22]
def hash160_to_p2pkh(h160, *, net=None):
if net is None:
net = constants.net
return hash160_to_b58_address(h160, net.ADDRTYPE_P2PKH)
def hash160_to_p2sh(h160, *, net=None):
if net is None:
net = constants.net
return hash160_to_b58_address(h160, net.ADDRTYPE_P2SH)
def public_key_to_p2pkh(public_key):
return hash160_to_p2pkh(hash_160(public_key))
def pubkey_to_address(txin_type, pubkey):
if txin_type == 'p2pkh':
return public_key_to_p2pkh(bfh(pubkey))
else:
raise NotImplementedError(txin_type)
def redeem_script_to_address(txin_type, redeem_script):
if txin_type == 'p2sh':
return hash160_to_p2sh(hash_160(bfh(redeem_script)))
else:
raise NotImplementedError(txin_type)
def script_to_address(script, *, net=None):
from .transaction import get_address_from_output_script
t, addr = get_address_from_output_script(bfh(script), net=net)
assert t == TYPE_ADDRESS
return addr
def address_to_script(addr, *, net=None):
if net is None:
net = constants.net
addrtype, hash_160 = b58_address_to_hash160(addr)
if addrtype == net.ADDRTYPE_P2PKH:
script = '76a9' # op_dup, op_hash_160
script += push_script(bh2u(hash_160))
script += '88ac' # op_equalverify, op_checksig
elif addrtype == net.ADDRTYPE_P2SH:
script = 'a9' # op_hash_160
script += push_script(bh2u(hash_160))
script += '87' # op_equal
else:
raise BitcoinException('unknown address type: {}'.format(addrtype))
return script
def address_to_scripthash(addr):
script = address_to_script(addr)
return script_to_scripthash(script)
def script_to_scripthash(script):
h = sha256(bytes.fromhex(script))[0:32]
return bh2u(bytes(reversed(h)))
def public_key_to_p2pk_script(pubkey):
script = push_script(pubkey)
script += 'ac' # op_checksig
return script
__b58chars = b'123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
assert len(__b58chars) == 58
__b43chars = b'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ$*+-./:'
assert len(__b43chars) == 43
def base_encode(v, base):
""" encode v, which is a string of bytes, to base58."""
assert_bytes(v)
if base not in (58, 43):
raise ValueError('not supported base: {}'.format(base))
chars = __b58chars
if base == 43:
chars = __b43chars
long_value = 0
for (i, c) in enumerate(v[::-1]):
long_value += (256**i) * c
result = bytearray()
while long_value >= base:
div, mod = divmod(long_value, base)
result.append(chars[mod])
long_value = div
result.append(chars[long_value])
# bitcoinprivate does a little leading-zero-compression:
# leading 0-bytes in the input become leading-1s
nPad = 0
for c in v:
if c == 0x00:
nPad += 1
else:
break
result.extend([chars[0]] * nPad)
result.reverse()
return result.decode('ascii')
def base_decode(v, length, base):
""" decode v into a string of len bytes."""
# assert_bytes(v)
v = to_bytes(v, 'ascii')
if base not in (58, 43):
raise ValueError('not supported base: {}'.format(base))
chars = __b58chars
if base == 43:
chars = __b43chars
long_value = 0
for (i, c) in enumerate(v[::-1]):
digit = chars.find(bytes([c]))
if digit == -1:
raise ValueError('Forbidden character {} for base {}'.format(c, base))
long_value += digit * (base**i)
result = bytearray()
while long_value >= 256:
div, mod = divmod(long_value, 256)
result.append(mod)
long_value = div
result.append(long_value)
nPad = 0
for c in v:
if c == chars[0]:
nPad += 1
else:
break
result.extend(b'\x00' * nPad)
if length is not None and len(result) != length:
return None
result.reverse()
return bytes(result)
class InvalidChecksum(Exception):
pass
def EncodeBase58Check(vchIn):
hash = Hash(vchIn)
return base_encode(vchIn + hash[0:4], base=58)
def DecodeBase58Check(psz):
vchRet = base_decode(psz, None, base=58)
key = vchRet[0:-4]
csum = vchRet[-4:]
hash = Hash(key)
cs32 = hash[0:4]
if cs32 != csum:
raise InvalidChecksum('expected {}, actual {}'.format(bh2u(cs32), bh2u(csum)))
else:
return key
# backwards compat
# extended WIF for segwit (used in 3.0.x; but still used internally)
# the keys in this dict should be a superset of what Imported Wallets can import
SCRIPT_TYPES = {
'p2pkh':0,
'p2sh':5,
}
def serialize_privkey(secret, compressed, txin_type, internal_use=False):
if internal_use:
prefix = bytes([(SCRIPT_TYPES[txin_type] + constants.net.WIF_PREFIX) & 255])
else:
prefix = bytes([constants.net.WIF_PREFIX])
suffix = b'\01' if compressed else b''
vchIn = prefix + secret + suffix
base58_wif = EncodeBase58Check(vchIn)
if internal_use:
return base58_wif
else:
return '{}:{}'.format(txin_type, base58_wif)
def deserialize_privkey(key):
if is_minikey(key):
return 'p2pkh', minikey_to_private_key(key), True
txin_type = None
if ':' in key:
txin_type, key = key.split(sep=':', maxsplit=1)
if txin_type not in SCRIPT_TYPES:
raise BitcoinException('unknown script type: {}'.format(txin_type))
try:
vch = DecodeBase58Check(key)
except BaseException:
neutered_privkey = str(key)[:3] + '..' + str(key)[-2:]
raise BitcoinException("cannot deserialize privkey {}"
.format(neutered_privkey))
if txin_type is None:
# keys exported in version 3.0.x encoded script type in first byte
txin_type = inv_dict(SCRIPT_TYPES)[vch[0] - constants.net.WIF_PREFIX]
else:
# all other keys must have a fixed first byte
if vch[0] != constants.net.WIF_PREFIX:
raise BitcoinException('invalid prefix ({}) for WIF key'.format(vch[0]))
if len(vch) not in [33, 34]:
raise BitcoinException('invalid vch len for WIF key: {}'.format(len(vch)))
compressed = len(vch) == 34
return txin_type, vch[1:33], compressed
def regenerate_key(pk):
assert len(pk) == 32
return EC_KEY(pk)
def GetPubKey(pubkey, compressed=False):
return i2o_ECPublicKey(pubkey, compressed)
def GetSecret(pkey):
return bfh('%064x' % pkey.secret)
def is_compressed(sec):
return deserialize_privkey(sec)[2]
def public_key_from_private_key(pk, compressed):
pkey = regenerate_key(pk)
public_key = GetPubKey(pkey.pubkey, compressed)
return bh2u(public_key)
def address_from_private_key(sec):
txin_type, privkey, compressed = deserialize_privkey(sec)
public_key = public_key_from_private_key(privkey, compressed)
return pubkey_to_address(txin_type, public_key)
def is_b58_address(addr):
try:
addrtype, h = b58_address_to_hash160(addr)
except Exception as e:
return False
if addrtype not in [constants.net.ADDRTYPE_P2PKH, constants.net.ADDRTYPE_P2SH]:
return False
return addr == hash160_to_b58_address(h, addrtype)
def is_address(addr):
return is_b58_address(addr)
def is_private_key(key):
try:
k = deserialize_privkey(key)
return k is not False
except:
return False
########### end pywallet functions #######################
def is_minikey(text):
# Minikeys are typically 22 or 30 characters, but this routine
# permits any length of 20 or more provided the minikey is valid.
# A valid minikey must begin with an 'S', be in base58, and when
# suffixed with '?' have its SHA256 hash begin with a zero byte.
# They are widely used in Casascius physical bitcoins.
return (len(text) >= 20 and text[0] == 'S'
and all(ord(c) in __b58chars for c in text)
and sha256(text + '?')[0] == 0x00)
def minikey_to_private_key(text):
return sha256(text)
from ecdsa.ecdsa import curve_secp256k1, generator_secp256k1
from ecdsa.curves import SECP256k1
from ecdsa.ellipticcurve import Point
from ecdsa.util import string_to_number, number_to_string
def msg_magic(message):
length = bfh(var_int(len(message)))
return b"\x18bitcoinprivate Signed Message:\n" + length + message
def verify_message(address, sig, message):
assert_bytes(sig, message)
try:
h = Hash(msg_magic(message))
public_key, compressed = pubkey_from_signature(sig, h)
# check public key using the address
pubkey = point_to_ser(public_key.pubkey.point, compressed)
for txin_type in ['p2pkh']:
addr = pubkey_to_address(txin_type, bh2u(pubkey))
if address == addr:
break
else:
raise Exception("Bad signature")
# check message
public_key.verify_digest(sig[1:], h, sigdecode = ecdsa.util.sigdecode_string)
return True
except Exception as e:
print_error("Verification error: {0}".format(e))
return False
def encrypt_message(message, pubkey, magic=b'BIE1'):
return EC_KEY.encrypt_message(message, bfh(pubkey), magic)
def chunks(l, n):
return [l[i:i+n] for i in range(0, len(l), n)]
def ECC_YfromX(x,curved=curve_secp256k1, odd=True):
_p = curved.p()
_a = curved.a()
_b = curved.b()
for offset in range(128):
Mx = x + offset
My2 = pow(Mx, 3, _p) + _a * pow(Mx, 2, _p) + _b % _p
My = pow(My2, (_p+1)//4, _p )
if curved.contains_point(Mx,My):
if odd == bool(My&1):
return [My,offset]
return [_p-My,offset]
raise Exception('ECC_YfromX: No Y found')
def negative_point(P):
return Point( P.curve(), P.x(), -P.y(), P.order() )
def point_to_ser(P, comp=True ):
if comp:
return bfh( ('%02x'%(2+(P.y()&1)))+('%064x'%P.x()) )
return bfh( '04'+('%064x'%P.x())+('%064x'%P.y()) )
def ser_to_point(Aser):
curve = curve_secp256k1
generator = generator_secp256k1
_r = generator.order()
assert Aser[0] in [0x02, 0x03, 0x04]
if Aser[0] == 0x04:
return Point( curve, string_to_number(Aser[1:33]), string_to_number(Aser[33:]), _r )
Mx = string_to_number(Aser[1:])
return Point( curve, Mx, ECC_YfromX(Mx, curve, Aser[0] == 0x03)[0], _r )
class MyVerifyingKey(ecdsa.VerifyingKey):
@classmethod
def from_signature(klass, sig, recid, h, curve):
""" See http://www.secg.org/download/aid-780/sec1-v2.pdf, chapter 4.1.6 """
from ecdsa import util, numbertheory
from . import msqr
curveFp = curve.curve
G = curve.generator
order = G.order()
# extract r,s from signature
r, s = util.sigdecode_string(sig, order)
# 1.1
x = r + (recid//2) * order
# 1.3
alpha = ( x * x * x + curveFp.a() * x + curveFp.b() ) % curveFp.p()
beta = msqr.modular_sqrt(alpha, curveFp.p())
y = beta if (beta - recid) % 2 == 0 else curveFp.p() - beta
# 1.4 the constructor checks that nR is at infinity
R = Point(curveFp, x, y, order)
# 1.5 compute e from message:
e = string_to_number(h)
minus_e = -e % order
# 1.6 compute Q = r^-1 (sR - eG)
inv_r = numbertheory.inverse_mod(r,order)
Q = inv_r * ( s * R + minus_e * G )
return klass.from_public_point( Q, curve )
def pubkey_from_signature(sig, h):
if len(sig) != 65:
raise Exception("Wrong encoding")
nV = sig[0]
if nV < 27 or nV >= 35:
raise Exception("Bad encoding")
if nV >= 31:
compressed = True
nV -= 4
else:
compressed = False
recid = nV - 27
return MyVerifyingKey.from_signature(sig[1:], recid, h, curve = SECP256k1), compressed
class MySigningKey(ecdsa.SigningKey):
"""Enforce low S values in signatures"""
def sign_number(self, number, entropy=None, k=None):
curve = SECP256k1
G = curve.generator
order = G.order()
r, s = ecdsa.SigningKey.sign_number(self, number, entropy, k)
if s > order//2:
s = order - s
return r, s
class EC_KEY(object):
def __init__( self, k ):
secret = string_to_number(k)
self.pubkey = ecdsa.ecdsa.Public_key( generator_secp256k1, generator_secp256k1 * secret )
self.privkey = ecdsa.ecdsa.Private_key( self.pubkey, secret )
self.secret = secret
def get_public_key(self, compressed=True):
return bh2u(point_to_ser(self.pubkey.point, compressed))
def sign(self, msg_hash):
private_key = MySigningKey.from_secret_exponent(self.secret, curve = SECP256k1)
public_key = private_key.get_verifying_key()
signature = private_key.sign_digest_deterministic(msg_hash, hashfunc=hashlib.sha256, sigencode = ecdsa.util.sigencode_string)
assert public_key.verify_digest(signature, msg_hash, sigdecode = ecdsa.util.sigdecode_string)
return signature
def sign_message(self, message, is_compressed):
message = to_bytes(message, 'utf8')
signature = self.sign(Hash(msg_magic(message)))
for i in range(4):
sig = bytes([27 + i + (4 if is_compressed else 0)]) + signature
try:
self.verify_message(sig, message)
return sig
except Exception as e:
continue
else:
raise Exception("error: cannot sign message")
def verify_message(self, sig, message):
assert_bytes(message)
h = Hash(msg_magic(message))
public_key, compressed = pubkey_from_signature(sig, h)
# check public key
if point_to_ser(public_key.pubkey.point, compressed) != point_to_ser(self.pubkey.point, compressed):
raise Exception("Bad signature")
# check message
public_key.verify_digest(sig[1:], h, sigdecode = ecdsa.util.sigdecode_string)
# ECIES encryption/decryption methods; AES-128-CBC with PKCS7 is used as the cipher; hmac-sha256 is used as the mac
@classmethod
def encrypt_message(self, message, pubkey, magic=b'BIE1'):
assert_bytes(message)
pk = ser_to_point(pubkey)
if not ecdsa.ecdsa.point_is_valid(generator_secp256k1, pk.x(), pk.y()):
raise Exception('invalid pubkey')
ephemeral_exponent = number_to_string(ecdsa.util.randrange(pow(2,256)), generator_secp256k1.order())
ephemeral = EC_KEY(ephemeral_exponent)
ecdh_key = point_to_ser(pk * ephemeral.privkey.secret_multiplier)
key = hashlib.sha512(ecdh_key).digest()
iv, key_e, key_m = key[0:16], key[16:32], key[32:]
ciphertext = aes_encrypt_with_iv(key_e, iv, message)
ephemeral_pubkey = bfh(ephemeral.get_public_key(compressed=True))
encrypted = magic + ephemeral_pubkey + ciphertext
mac = hmac.new(key_m, encrypted, hashlib.sha256).digest()
return base64.b64encode(encrypted + mac)
def decrypt_message(self, encrypted, magic=b'BIE1'):
encrypted = base64.b64decode(encrypted)
if len(encrypted) < 85:
raise Exception('invalid ciphertext: length')
magic_found = encrypted[:4]
ephemeral_pubkey = encrypted[4:37]
ciphertext = encrypted[37:-32]
mac = encrypted[-32:]
if magic_found != magic:
raise Exception('invalid ciphertext: invalid magic bytes')
try:
ephemeral_pubkey = ser_to_point(ephemeral_pubkey)
except AssertionError as e:
raise Exception('invalid ciphertext: invalid ephemeral pubkey')
if not ecdsa.ecdsa.point_is_valid(generator_secp256k1, ephemeral_pubkey.x(), ephemeral_pubkey.y()):
raise Exception('invalid ciphertext: invalid ephemeral pubkey')
ecdh_key = point_to_ser(ephemeral_pubkey * self.privkey.secret_multiplier)
key = hashlib.sha512(ecdh_key).digest()
iv, key_e, key_m = key[0:16], key[16:32], key[32:]
if mac != hmac.new(key_m, encrypted[:-32], hashlib.sha256).digest():
raise InvalidPassword()
return aes_decrypt_with_iv(key_e, iv, ciphertext)
###################################### BIP32 ##############################
random_seed = lambda n: "%032x"%ecdsa.util.randrange( pow(2,n) )
BIP32_PRIME = 0x80000000
def get_pubkeys_from_secret(secret):
# public key
private_key = ecdsa.SigningKey.from_string( secret, curve = SECP256k1 )
public_key = private_key.get_verifying_key()
K = public_key.to_string()
K_compressed = GetPubKey(public_key.pubkey,True)
return K, K_compressed
# Child private key derivation function (from master private key)
# k = master private key (32 bytes)
# c = master chain code (extra entropy for key derivation) (32 bytes)
# n = the index of the key we want to derive. (only 32 bits will be used)
# If n is negative (i.e. the 32nd bit is set), the resulting private key's
# corresponding public key can NOT be determined without the master private key.
# However, if n is positive, the resulting private key's corresponding
# public key can be determined without the master private key.
def CKD_priv(k, c, n):
is_prime = n & BIP32_PRIME
return _CKD_priv(k, c, bfh(rev_hex(int_to_hex(n,4))), is_prime)
def _CKD_priv(k, c, s, is_prime):
order = generator_secp256k1.order()
keypair = EC_KEY(k)
cK = GetPubKey(keypair.pubkey,True)
data = bytes([0]) + k + s if is_prime else cK + s
I = hmac.new(c, data, hashlib.sha512).digest()
k_n = number_to_string( (string_to_number(I[0:32]) + string_to_number(k)) % order , order )
c_n = I[32:]
return k_n, c_n
# Child public key derivation function (from public key only)
# K = master public key
# c = master chain code
# n = index of key we want to derive
# This function allows us to find the nth public key, as long as n is
# non-negative. If n is negative, we need the master private key to find it.
def CKD_pub(cK, c, n):
if n & BIP32_PRIME: raise
return _CKD_pub(cK, c, bfh(rev_hex(int_to_hex(n,4))))
# helper function, callable with arbitrary string
def _CKD_pub(cK, c, s):
order = generator_secp256k1.order()
I = hmac.new(c, cK + s, hashlib.sha512).digest()
curve = SECP256k1
pubkey_point = string_to_number(I[0:32])*curve.generator + ser_to_point(cK)
public_key = ecdsa.VerifyingKey.from_public_point( pubkey_point, curve = SECP256k1 )
c_n = I[32:]
cK_n = GetPubKey(public_key.pubkey,True)
return cK_n, c_n
def xprv_header(xtype, *, net=None):
if net is None:
net = constants.net
return bfh("%08x" % net.XPRV_HEADERS[xtype])
def xpub_header(xtype, *, net=None):
if net is None:
net = constants.net
return bfh("%08x" % net.XPUB_HEADERS[xtype])
def serialize_xprv(xtype, c, k, depth=0, fingerprint=b'\x00'*4,
child_number=b'\x00'*4, *, net=None):
xprv = xprv_header(xtype, net=net) \
+ bytes([depth]) + fingerprint + child_number + c + bytes([0]) + k
return EncodeBase58Check(xprv)
def serialize_xpub(xtype, c, cK, depth=0, fingerprint=b'\x00'*4,
child_number=b'\x00'*4, *, net=None):
xpub = xpub_header(xtype, net=net) \
+ bytes([depth]) + fingerprint + child_number + c + cK
return EncodeBase58Check(xpub)
def deserialize_xkey(xkey, prv, *, net=None):
if net is None:
net = constants.net
xkey = DecodeBase58Check(xkey)
if len(xkey) != 78:
raise BitcoinException('Invalid length for extended key: {}'
.format(len(xkey)))
depth = xkey[4]
fingerprint = xkey[5:9]
child_number = xkey[9:13]
c = xkey[13:13+32]
header = int('0x' + bh2u(xkey[0:4]), 16)
headers = net.XPRV_HEADERS if prv else net.XPUB_HEADERS
if header not in headers.values():
raise BitcoinException('Invalid extended key format: {}'
.format(hex(header)))
xtype = list(headers.keys())[list(headers.values()).index(header)]
n = 33 if prv else 32
K_or_k = xkey[13+n:]
return xtype, depth, fingerprint, child_number, c, K_or_k
def deserialize_xpub(xkey, *, net=None):
return deserialize_xkey(xkey, False, net=net)
def deserialize_xprv(xkey, *, net=None):
return deserialize_xkey(xkey, True, net=net)
def xpub_type(x):
return deserialize_xpub(x)[0]
def is_xpub(text):
try:
deserialize_xpub(text)
return True
except:
return False
def is_xprv(text):
try:
deserialize_xprv(text)
return True
except:
return False
def xpub_from_xprv(xprv):
xtype, depth, fingerprint, child_number, c, k = deserialize_xprv(xprv)
K, cK = get_pubkeys_from_secret(k)
return serialize_xpub(xtype, c, cK, depth, fingerprint, child_number)
def bip32_root(seed, xtype):
I = hmac.new(b"bitcoinprivate seed", seed, hashlib.sha512).digest()
master_k = I[0:32]
master_c = I[32:]
K, cK = get_pubkeys_from_secret(master_k)
xprv = serialize_xprv(xtype, master_c, master_k)
xpub = serialize_xpub(xtype, master_c, cK)
return xprv, xpub
def xpub_from_pubkey(xtype, cK):
assert cK[0] in [0x02, 0x03]
return serialize_xpub(xtype, b'\x00'*32, cK)
def bip32_derivation(s):
if not s.startswith('m/'):
raise ValueError('invalid bip32 derivation path: {}'.format(s))
s = s[2:]
for n in s.split('/'):
if n == '': continue
i = int(n[:-1]) + BIP32_PRIME if n[-1] == "'" else int(n)
yield i
def is_bip32_derivation(x):
try:
[ i for i in bip32_derivation(x)]
return True
except :
return False
def bip32_private_derivation(xprv, branch, sequence):
if not sequence.startswith(branch):
raise ValueError('incompatible branch ({}) and sequence ({})'
.format(branch, sequence))
if branch == sequence:
return xprv, xpub_from_xprv(xprv)
xtype, depth, fingerprint, child_number, c, k = deserialize_xprv(xprv)
sequence = sequence[len(branch):]
for n in sequence.split('/'):
if n == '': continue
i = int(n[:-1]) + BIP32_PRIME if n[-1] == "'" else int(n)
parent_k = k
k, c = CKD_priv(k, c, i)
depth += 1
_, parent_cK = get_pubkeys_from_secret(parent_k)
fingerprint = hash_160(parent_cK)[0:4]
child_number = bfh("%08X"%i)
K, cK = get_pubkeys_from_secret(k)
xpub = serialize_xpub(xtype, c, cK, depth, fingerprint, child_number)
xprv = serialize_xprv(xtype, c, k, depth, fingerprint, child_number)
return xprv, xpub
def bip32_public_derivation(xpub, branch, sequence):
xtype, depth, fingerprint, child_number, c, cK = deserialize_xpub(xpub)
if not sequence.startswith(branch):
raise ValueError('incompatible branch ({}) and sequence ({})'
.format(branch, sequence))
sequence = sequence[len(branch):]
for n in sequence.split('/'):
if n == '': continue
i = int(n)
parent_cK = cK
cK, c = CKD_pub(cK, c, i)
depth += 1
fingerprint = hash_160(parent_cK)[0:4]
child_number = bfh("%08X"%i)
return serialize_xpub(xtype, c, cK, depth, fingerprint, child_number)
def bip32_private_key(sequence, k, chain):
for i in sequence:
k, chain = CKD_priv(k, chain, i)
return k
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