second pbkdf2 implementation

This commit is contained in:
idaapayo 2022-01-19 14:37:22 +03:00
parent 01598a8c59
commit 1f5d057a9a
2 changed files with 63 additions and 29 deletions

View File

@ -13,19 +13,20 @@ import sha3
# local imports
from funga.error import (
DecryptError,
KeyfileError,
)
DecryptError,
KeyfileError,
)
from funga.eth.encoding import private_key_to_address
logg = logging.getLogger(__name__)
algo_keywords = [
'aes-128-ctr',
]
]
hash_keywords = [
'scrypt'
]
'scrypt',
'pbkdf2'
]
default_kdfparams = {
'dklen': 32,
@ -33,8 +34,14 @@ default_kdfparams = {
'p': 1,
'r': 8,
'salt': os.urandom(32).hex(),
}
}
pbkdf2_kdfparams = {
'c': 100000,
'dklen': 32,
'prf': 'sha256',
'salt': os.urandom(32).hex(),
}
def to_mac(mac_key, ciphertext_bytes):
h = sha3.keccak_256()
@ -47,17 +54,35 @@ 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'])
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)
return hashlib.scrypt(passphrase.encode('utf-8'), salt=salt, n=n, p=p, r=r, maxmem=1024 * 1024 * 1024,
dklen=dklen)
@staticmethod
def from_pbkdf2(kdfparams=pbkdf2_kdfparams, passphrase=''):
hashname = kdfparams['prf']
pwd = passphrase.encode('utf-8')
salt = bytes.fromhex(kdfparams['salt'])
itr = int(kdfparams['c'])
dklen = int(kdfparams['dklen'])
derived_key = hashlib.pbkdf2_hmac(
hash_name=hashname,
password=pwd,
salt=salt,
iterations=itr,
dklen=dklen
)
return derived_key
class Ciphers:
aes_128_block_size = 1 << 7
aes_iv_len = 16
@ -68,7 +93,6 @@ class Ciphers:
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)
@ -77,11 +101,19 @@ class Ciphers:
return ciphertext
def to_dict(private_key_bytes, passphrase=''):
def to_dict(private_key_bytes, kdf :str, passphrase=''):
private_key = coincurve.PrivateKey(secret=private_key_bytes)
encryption_key = Hashes.from_scrypt(passphrase=passphrase)
if kdf == 'scrypt':
encryption_key = Hashes.from_scrypt(passphrase=passphrase)
kdfparams = default_kdfparams
elif kdf == 'pbkdf2':
encryption_key = Hashes.from_pbkdf2(passphrase=passphrase)
kdfparams = pbkdf2_kdfparams
else:
raise NotImplementedError("KDF not implemented: {0}".format(kdf))
address_hex = private_key_to_address(private_key)
iv_bytes = os.urandom(Ciphers.aes_iv_len)
@ -95,11 +127,11 @@ def to_dict(private_key_bytes, passphrase=''):
'ciphertext': ciphertext_bytes.hex(),
'cipherparams': {
'iv': iv_bytes.hex(),
},
'kdf': 'scrypt',
'kdfparams': default_kdfparams,
},
'kdf': kdf,
'kdfparams': kdfparams,
'mac': mac.hex(),
}
}
uu = uuid.uuid1()
o = {
@ -107,12 +139,11 @@ def to_dict(private_key_bytes, passphrase=''):
'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))
@ -121,19 +152,19 @@ def from_dict(o, passphrase=''):
if kdf not in hash_keywords:
raise NotImplementedError('kdf "{}" not implemented'.format(kdf))
m = getattr(Hashes, 'from_{}'.format(kdf.replace('-', '_')))
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:
@ -145,7 +176,6 @@ def from_dict(o, passphrase=''):
def from_file(filepath, passphrase=''):
f = open(filepath, 'r')
try:
o = json.load(f)

View File

@ -16,6 +16,10 @@ from funga.eth.keystore.keyfile import (
from_file,
to_dict,
)
# from testkeyfile import (
# from_file,
# to_dict
# )
from funga.eth.encoding import (
private_key_to_address,
private_key_from_bytes,
@ -77,7 +81,7 @@ def main():
else:
pk_bytes = os.urandom(32)
pk = coincurve.PrivateKey(secret=pk_bytes)
o = to_dict(pk_bytes, passphrase)
o = to_dict(pk_bytes, 'pbkdf2', passphrase)
r = json.dumps(o)
print(r)