staking-deposit-cli/eth2deposit/key_handling/key_derivation/mnemonic.py
Carl Beekhuizen 353c40215f
Merge branch 'dev' into carl_eip2335_unicode
* dev: (22 commits)
  Remove BLS incompatability warning
  Adds preproduction warning
  Adds typing & Moves global variables into pytest function args
  Linting fixes
  Test key_info != b''
  import pytest into test_tree
  Apply suggestions from @hwwhww's code review
  Fix lint
  Add Altona setting
  Remove extra newline (lint)
  Update tests for new EIP2333 (bls v2 compliant HKDF_mod_r)
  Rename json file fields
  Create uuid at execution time instead of class attribute
  Add uuid test
  Fix key path
  Add Witti
  gitignore dist/
  Revert to DepositMessage & DepositData as per spec
  Add fork_version
  adds build/ to .gitignore
  ...
2020-07-06 21:19:07 +02:00

65 lines
2.0 KiB
Python

import os
from unicodedata import normalize
from secrets import randbits
from typing import (
Optional,
Sequence,
Tuple,
)
from eth2deposit.utils.crypto import (
SHA256,
PBKDF2,
)
def _get_word_list(language: str, path: str) -> Sequence[str]:
return open(os.path.join(path, '%s.txt' % language), encoding='utf-8').readlines()
def _get_word(*, word_list: Sequence[str], index: int) -> str:
assert index < 2048
return word_list[index][:-1]
def get_seed(*, mnemonic: str, password: str) -> bytes:
"""
Derive the seed for the pre-image root of the tree.
Ref: https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#from-mnemonic-to-seed
"""
encoded_mnemonic = normalize('NFKD', mnemonic).encode('utf-8')
salt = normalize('NFKD', 'mnemonic' + password).encode('utf-8')
return PBKDF2(password=encoded_mnemonic, salt=salt, dklen=64, c=2048, prf='sha512')
def get_languages(path: str) -> Tuple[str, ...]:
"""
Walk the `path` and list all the languages with word-lists available.
"""
(_, _, filenames) = next(os.walk(path))
languages = tuple([name[:-4] for name in filenames])
return languages
def get_mnemonic(*, language: str, words_path: str, entropy: Optional[bytes]=None) -> str:
"""
Return a mnemonic string in a given `language` based on `entropy`.
"""
if entropy is None:
entropy = randbits(256).to_bytes(32, 'big')
entropy_length = len(entropy) * 8
assert entropy_length in range(128, 257, 32)
checksum_length = (entropy_length // 32)
checksum = int.from_bytes(SHA256(entropy), 'big') >> 256 - checksum_length
entropy_bits = int.from_bytes(entropy, 'big') << checksum_length
entropy_bits += checksum
entropy_length += checksum_length
mnemonic = []
word_list = _get_word_list(language, words_path)
for i in range(entropy_length // 11 - 1, -1, -1):
index = (entropy_bits >> i * 11) & 2**11 - 1
word = _get_word(word_list=word_list, index=index)
mnemonic.append(word)
return ' '.join(mnemonic)