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Speed up bip39.next_char #41

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Speed up bip39.next_char #41

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41 changes: 18 additions & 23 deletions ngu/bip39.py
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Original file line number Diff line number Diff line change
Expand Up @@ -294,7 +294,7 @@


def get_word_index(word):
"input string word; return int index in wordlist, or ValueError"
# input string word; return int index in wordlist, or ValueError
# - also accepts just first four distinctive characters of the word

try:
Expand All @@ -316,7 +316,7 @@ def get_word_index(word):


def b2a_words(msg):
"map binary to words, including a few bits of checksum, per BIP39 spec"
# map binary to words, including a few bits of checksum, per BIP39 spec
l = len(msg)
assert 16 <= l <= 32
assert l % 4 == 0
Expand Down Expand Up @@ -345,7 +345,7 @@ def b2a_words(msg):


def _split_lookup(phrase):
"decode & lookup only"
# decode & lookup only

if isinstance(phrase, str):
phrase = phrase.split()
Expand All @@ -360,7 +360,7 @@ def _split_lookup(phrase):
return num, rv

def a2b_words(phrase):
"decode, raise on bad checksum"
# decode, raise on bad checksum

num, rv = _split_lookup(phrase)

Expand All @@ -382,7 +382,7 @@ def a2b_words(phrase):
return bits

def a2b_words_guess(phrase):
"generate a list of possible final words"
# generate a list of possible final words
num, rv = _split_lookup(phrase)

if num not in { 11, 14, 17, 20, 23 }:
Expand All @@ -409,30 +409,25 @@ def next_char(prefix):
assert pl >= 1

try:
wn = wordlist_en.index(prefix)
if pl >= 4:
return (True, '', wordlist_en[wn])
exact = True
except ValueError:
exact = False
# skip down until first 1-2 char(s) match
try:
wn = _lookup[prefix[0:2]]
except KeyError:
# 2-prefix not in list
return (False, '', None)
wn = _lookup[prefix[0:2]]
except KeyError:
# prefix not in the _lookup list
return False, '', None

first = None
count = 0

exact = False
chars = []
for wn in range(wn, 0x800):
word = wordlist_en[wn]
if word[0:pl] > prefix: break
if word[0:pl] == prefix:
wc = word[0:pl]
if wc > prefix: break # lexicographical ordering
if wc == prefix:
if word == prefix:
exact = True
if pl >= 4:
# they gave 4+ letter prefix of correct word; they're done
return (True, '', word)
return True, '', word

if not count:
first = word
Expand All @@ -452,6 +447,6 @@ def master_secret(words, pw=b''):
import ngu
return ngu.hash.pbkdf2_sha512(words, salt, 2048)
except ImportError:
import wallycore
return wallycore.pbkdf2_hmac_sha512(words, salt, 0, 2048)
import hashlib
return hashlib.pbkdf2_hmac("sha512", words, salt, 2048, dklen=64)

3 changes: 3 additions & 0 deletions ngu/ngu_tests/test_bip39.py
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Original file line number Diff line number Diff line change
Expand Up @@ -64,10 +64,13 @@ def test_prefix():
assert bip39.next_char('dkfjh') == (False, '', None)
assert bip39.next_char('a') == (False, 'bcdefghilmnprstuvwx', None)
assert bip39.next_char('q') == (False, 'u', None)
assert bip39.next_char('x') == (False, '', None) # only char not in the _lookup
assert bip39.next_char('qu') == (False, 'aeio', None)
assert bip39.next_char('present') == (True, '', 'present')
assert bip39.next_char('zoo') == (True, '', 'zoo')
assert bip39.next_char('zo') == (False, 'no', None)
assert bip39.next_char('fat') == (True, 'ahi', None)
assert bip39.next_char('win') == (True, 'degknt', None)

wl = bip39.wordlist_en
for w in wl:
Expand Down