163 lines
6.0 KiB
Python
163 lines
6.0 KiB
Python
###############################################################################
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#
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# The MIT License (MIT)
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#
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# Copyright (c) 2018 Luis Teixeira
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# - copied & modified from https://github.com/vergl4s/ethereum-mnemonic-utils
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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#
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###############################################################################
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import hashlib
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import hmac
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import struct
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from base58 import b58encode_check
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from ecdsa.curves import SECP256k1
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BIP39_PBKDF2_ROUNDS = 2048
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BIP39_SALT_MODIFIER = "mnemonic"
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BIP32_PRIVDEV = 0x80000000
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BIP32_CURVE = SECP256k1
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BIP32_SEED_MODIFIER = b'Bitcoin seed'
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# https://github.com/ethereum/EIPs/issues/84#issuecomment-528213145
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LEDGER_ETH_DERIVATION_PATH = "m/44'/60'/0'/0"
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def mnemonic_to_bip39seed(mnemonic, passphrase):
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""" BIP39 seed from a mnemonic key.
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Logic adapted from https://github.com/trezor/python-mnemonic. """
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mnemonic = bytes(mnemonic, 'utf8')
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salt = bytes(BIP39_SALT_MODIFIER + passphrase, 'utf8')
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return hashlib.pbkdf2_hmac('sha512', mnemonic, salt, BIP39_PBKDF2_ROUNDS)
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def bip39seed_to_bip32masternode(seed):
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""" BIP32 master node derivation from a bip39 seed.
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Logic adapted from https://github.com/satoshilabs/slips/blob/master/slip-0010/testvectors.py. """
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h = hmac.new(BIP32_SEED_MODIFIER, seed, hashlib.sha512).digest()
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key, chain_code = h[:32], h[32:]
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return key, chain_code
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def derive_public_key(private_key):
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""" Public key from a private key.
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Logic adapted from https://github.com/satoshilabs/slips/blob/master/slip-0010/testvectors.py. """
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Q = int.from_bytes(private_key, byteorder='big') * BIP32_CURVE.generator
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xstr = int(Q.x()).to_bytes(32, byteorder='big')
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parity = Q.y() & 1
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return int(2 + parity).to_bytes(1, byteorder='big') + xstr
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def derive_bip32childkey(parent_key, parent_chain_code, i):
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""" Derives a child key from an existing key, i is current derivation parameter.
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Logic adapted from https://github.com/satoshilabs/slips/blob/master/slip-0010/testvectors.py. """
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assert len(parent_key) == 32
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assert len(parent_chain_code) == 32
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k = parent_chain_code
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if (i & BIP32_PRIVDEV) != 0:
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key = b'\x00' + parent_key
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else:
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key = derive_public_key(parent_key)
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d = key + struct.pack('>L', i)
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while True:
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h = hmac.new(k, d, hashlib.sha512).digest()
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key, chain_code = h[:32], h[32:]
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a = int.from_bytes(key, byteorder='big')
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b = int.from_bytes(parent_key, byteorder='big')
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key = (a + b) % BIP32_CURVE.order
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if a < BIP32_CURVE.order and key != 0:
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key = int(key).to_bytes(32, byteorder='big')
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break
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d = b'\x01' + h[32:] + struct.pack('>L', i)
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return key, chain_code
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def fingerprint(public_key):
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""" BIP32 fingerprint formula, used to get b58 serialized key. """
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return hashlib.new('ripemd160', hashlib.sha256(public_key).digest()).digest()[:4]
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def b58xprv(parent_fingerprint, private_key, chain, depth, childnr):
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""" Private key b58 serialization format. """
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raw = (b'\x04\x88\xad\xe4' + bytes(chr(depth), 'utf-8') + parent_fingerprint + int(childnr).to_bytes(
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4, byteorder='big') + chain + b'\x00' + private_key)
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return b58encode_check(raw)
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def b58xpub(parent_fingerprint, public_key, chain, depth, childnr):
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""" Public key b58 serialization format. """
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raw = (b'\x04\x88\xb2\x1e' + bytes(chr(depth), 'utf-8') + parent_fingerprint + int(childnr).to_bytes(
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4, byteorder='big') + chain + public_key)
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return b58encode_check(raw)
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def parse_derivation_path(str_derivation_path):
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""" Parses a derivation path such as "m/44'/60/0'/0" and returns
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list of integers for each element in path. """
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path = []
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if str_derivation_path[0:2] != 'm/':
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raise ValueError("Can't recognize derivation path. It should look like \"m/44'/60/0'/0\".")
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for i in str_derivation_path.lstrip('m/').split('/'):
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if "'" in i:
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path.append(BIP32_PRIVDEV + int(i[:-1]))
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else:
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path.append(int(i))
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return path
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def mnemonic_to_private_key(mnemonic, str_derivation_path=LEDGER_ETH_DERIVATION_PATH, passphrase=""):
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""" Performs all convertions to get a private key from a mnemonic sentence, including:
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BIP39 mnemonic to seed
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BIP32 seed to master key
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BIP32 child derivation of a path provided
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Parameters:
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mnemonic -- seed wordlist, usually with 24 words, that is used for ledger wallet backup
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str_derivation_path -- string that directs BIP32 key derivation, defaults to path
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used by ledger ETH wallet
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"""
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derivation_path = parse_derivation_path(str_derivation_path)
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bip39seed = mnemonic_to_bip39seed(mnemonic, passphrase)
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master_private_key, master_chain_code = bip39seed_to_bip32masternode(bip39seed)
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private_key, chain_code = master_private_key, master_chain_code
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for i in derivation_path:
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private_key, chain_code = derive_bip32childkey(private_key, chain_code, i)
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return private_key
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