AaronFiore/electrum
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extended seed prefix

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This commit is contained in:
ThomasV
2014-09-09 11:51:45 +02:00
parent c657212e5b
commit 6361abaf4d
5 changed files with 23 additions and 22 deletions
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13
lib/mnemonic.py
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@@ -27,7 +27,7 @@ import pbkdf2
from util import print_error
from bitcoin import is_old_seed, is_new_seed
import version
class Mnemonic(object):
# Seed derivation follows BIP39
@@ -89,11 +89,13 @@ class Mnemonic(object):
i = self.mnemonic_decode(seed)
return i % custom_entropy == 0
def make_seed(self, num_bits=128, custom_entropy=1):
def make_seed(self, num_bits=128, prefix=version.SEED_BIP44, custom_entropy=1):
n = int(math.ceil(math.log(custom_entropy,2)))
# bits of entropy used by the prefix
k = len(prefix)*4
# we add at least 16 bits
n_added = max(16, 8 + num_bits - n)
print_error("make_seed: adding %d bits"%n_added)
n_added = max(16, k + num_bits - n)
print_error("make_seed", prefix, "adding %d bits"%n_added)
my_entropy = ecdsa.util.randrange( pow(2, n_added) )
nonce = 0
while True:
@@ -103,8 +105,7 @@ class Mnemonic(object):
assert i == self.mnemonic_decode(seed)
if is_old_seed(seed):
continue
# this removes 8 bits of entropy
if is_new_seed(seed):
if is_new_seed(seed, prefix):
break
print_error('%d words'%len(seed.split()))
return seed