def decode(secret, _bip39pw=''):
# expecting 72-bytes of secret payload; decode contents into objects
# returns:
# type, secrets bytes, HDNode(root)
#
marker = secret[0]
hd = ngu.hdnode.HDNode()
if marker == 0x01:
# xprv => BIP-32 private key values
ch, pk = secret[1:33], secret[33:65]
assert not _bip39pw
hd.from_chaincode_privkey(ch, pk)
return 'xprv', ch + pk, hd
if marker & 0x80:
# seed phrase
ll = ((marker & 0x3) + 2) * 8
# note:
# - byte length > number of words
# - not storing checksum
assert ll in [16, 24, 32]
# make master secret, using the memonic words, and passphrase (or empty string)
seed_bits = secret[1:1 + ll]
ms = bip39.master_secret(bip39.b2a_words(seed_bits), _bip39pw)
hd.from_master(ms)
return 'words', seed_bits, hd
else:
# variable-length master secret for BIP-32
vlen = secret[0]
assert 16 <= vlen <= 64
assert not _bip39pw
ms = secret[1:1 + vlen]
hd = hd.from_master(ms)
return 'master', ms, hd
def test_vectors():
for raw, words, ms, _ in b39_vectors.english[0:10]:
assert bip39.a2b_words(words) == a2b_hex(raw)
got = bip39.master_secret(words.encode('utf'), a2b_hex('5452455a4f52'))
assert got == a2b_hex(ms)