forked from chaintool/funga-eth
173 lines
4.3 KiB
Python
173 lines
4.3 KiB
Python
# standard imports
|
|
import os
|
|
import hashlib
|
|
import logging
|
|
import json
|
|
import uuid
|
|
|
|
# external imports
|
|
import coincurve
|
|
from Crypto.Cipher import AES
|
|
from Crypto.Util import Counter
|
|
import sha3
|
|
|
|
# local imports
|
|
from funga.error import (
|
|
DecryptError,
|
|
KeyfileError,
|
|
)
|
|
from funga.eth.encoding import private_key_to_address
|
|
|
|
logg = logging.getLogger(__name__)
|
|
|
|
algo_keywords = [
|
|
'aes-128-ctr',
|
|
]
|
|
hash_keywords = [
|
|
'scrypt'
|
|
]
|
|
|
|
default_kdfparams = {
|
|
'dklen': 32,
|
|
'n': 1 << 18,
|
|
'p': 1,
|
|
'r': 8,
|
|
'salt': os.urandom(32).hex(),
|
|
}
|
|
|
|
|
|
def to_mac(mac_key, ciphertext_bytes):
|
|
h = sha3.keccak_256()
|
|
h.update(mac_key)
|
|
h.update(ciphertext_bytes)
|
|
return h.digest()
|
|
|
|
|
|
class Hashes:
|
|
|
|
@staticmethod
|
|
def from_scrypt(kdfparams=default_kdfparams, passphrase=''):
|
|
dklen = int(kdfparams['dklen'])
|
|
n = int(kdfparams['n'])
|
|
p = int(kdfparams['p'])
|
|
r = int(kdfparams['r'])
|
|
salt = bytes.fromhex(kdfparams['salt'])
|
|
|
|
return hashlib.scrypt(passphrase.encode('utf-8'), salt=salt,n=n, p=p, r=r, maxmem=1024*1024*1024, dklen=dklen)
|
|
|
|
|
|
class Ciphers:
|
|
|
|
aes_128_block_size = 1 << 7
|
|
aes_iv_len = 16
|
|
|
|
@staticmethod
|
|
def decrypt_aes_128_ctr(ciphertext, decryption_key, iv):
|
|
ctr = Counter.new(Ciphers.aes_128_block_size, initial_value=iv)
|
|
cipher = AES.new(decryption_key, AES.MODE_CTR, counter=ctr)
|
|
plaintext = cipher.decrypt(ciphertext)
|
|
return plaintext
|
|
|
|
|
|
@staticmethod
|
|
def encrypt_aes_128_ctr(plaintext, encryption_key, iv):
|
|
ctr = Counter.new(Ciphers.aes_128_block_size, initial_value=iv)
|
|
cipher = AES.new(encryption_key, AES.MODE_CTR, counter=ctr)
|
|
ciphertext = cipher.encrypt(plaintext)
|
|
return ciphertext
|
|
|
|
|
|
def to_dict(private_key_bytes, passphrase=''):
|
|
|
|
private_key = coincurve.PrivateKey(secret=private_key_bytes)
|
|
|
|
encryption_key = Hashes.from_scrypt(passphrase=passphrase)
|
|
|
|
address_hex = private_key_to_address(private_key)
|
|
iv_bytes = os.urandom(Ciphers.aes_iv_len)
|
|
iv = int.from_bytes(iv_bytes, 'big')
|
|
ciphertext_bytes = Ciphers.encrypt_aes_128_ctr(private_key.secret, encryption_key[:16], iv)
|
|
|
|
mac = to_mac(encryption_key[16:], ciphertext_bytes)
|
|
|
|
crypto_dict = {
|
|
'cipher': 'aes-128-ctr',
|
|
'ciphertext': ciphertext_bytes.hex(),
|
|
'cipherparams': {
|
|
'iv': iv_bytes.hex(),
|
|
},
|
|
'kdf': 'scrypt',
|
|
'kdfparams': default_kdfparams,
|
|
'mac': mac.hex(),
|
|
}
|
|
|
|
uu = uuid.uuid1()
|
|
o = {
|
|
'address': address_hex,
|
|
'version': 3,
|
|
'crypto': crypto_dict,
|
|
'id': str(uu),
|
|
}
|
|
return o
|
|
|
|
|
|
def from_dict(o, passphrase=''):
|
|
|
|
cipher = o['crypto']['cipher']
|
|
if cipher not in algo_keywords:
|
|
raise NotImplementedError('cipher "{}" not implemented'.format(cipher))
|
|
|
|
kdf = o['crypto']['kdf']
|
|
if kdf not in hash_keywords:
|
|
raise NotImplementedError('kdf "{}" not implemented'.format(kdf))
|
|
|
|
m = getattr(Hashes, 'from_{}'.format(kdf.replace('-', '_')))
|
|
decryption_key = m(o['crypto']['kdfparams'], passphrase)
|
|
|
|
control_mac = bytes.fromhex(o['crypto']['mac'])
|
|
iv_bytes = bytes.fromhex(o['crypto']['cipherparams']['iv'])
|
|
iv = int.from_bytes(iv_bytes, "big")
|
|
ciphertext_bytes = bytes.fromhex(o['crypto']['ciphertext'])
|
|
|
|
# check mac
|
|
calculated_mac = to_mac(decryption_key[16:], ciphertext_bytes)
|
|
if control_mac != calculated_mac:
|
|
raise DecryptError('mac mismatch when decrypting passphrase')
|
|
|
|
m = getattr(Ciphers, 'decrypt_{}'.format(cipher.replace('-', '_')))
|
|
|
|
try:
|
|
pk = m(ciphertext_bytes, decryption_key[:16], iv)
|
|
except AssertionError as e:
|
|
raise DecryptError('could not decrypt keyfile: {}'.format(e))
|
|
|
|
return pk
|
|
|
|
|
|
def from_file(filepath, passphrase=''):
|
|
|
|
f = open(filepath, 'r')
|
|
try:
|
|
o = json.load(f)
|
|
except json.decoder.JSONDecodeError as e:
|
|
f.close()
|
|
raise KeyfileError(e)
|
|
f.close()
|
|
|
|
return from_dict(o, passphrase)
|
|
|
|
|
|
def from_some(v, passphrase=''):
|
|
if isinstance(v, bytes):
|
|
v = v.decode('utf-8')
|
|
|
|
if isinstance(v, str):
|
|
try:
|
|
return from_file(v, passphrase)
|
|
except Exception:
|
|
logg.debug('keyfile parse as file fail')
|
|
pass
|
|
v = json.loads(v)
|
|
|
|
return from_dict(v, passphrase)
|