X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipherbreak.py;h=f1ab58e50a4f293368ef9d5382aef9dabf590420;hb=60a697926e04e109769b205534c08eeac712a28f;hp=0ca46062ddf4db5244f63402c60f91deb043c6f0;hpb=4e49d9a8c3379d16d1d721a14b072396568ecbcc;p=cipher-tools.git

diff --git a/cipherbreak.py b/cipherbreak.py
index 0ca4606..f1ab58e 100644
--- a/cipherbreak.py
+++ b/cipherbreak.py
@@ -569,7 +569,7 @@ def hill_break_worker(message, matrix, fitness):
                      fit, sanitise(plaintext)[:50]))
     return matrix, fit
 
-def bifid_break_mp(message, wordlist=keywords, fitness=Pletters,
+def bifid_break_mp(message, wordlist=keywords, fitness=Pletters, max_period=10,
                      number_of_solutions=1, chunksize=500):
     """Breaks a keyword substitution cipher using a dictionary and
     frequency analysis
@@ -577,18 +577,19 @@ def bifid_break_mp(message, wordlist=keywords, fitness=Pletters,
     >>> bifid_break_mp(bifid_encipher('this is a test message for the ' \
           'keyword decipherment', 'elephant', wrap_alphabet=KeywordWrapAlphabet.from_last), \
           wordlist=['cat', 'elephant', 'kangaroo']) # doctest: +ELLIPSIS
-    (('elephant', <KeywordWrapAlphabet.from_last: 2>), -52.834575011...)
+    (('elephant', <KeywordWrapAlphabet.from_last: 2>, 0), -52.834575011...)
     >>> bifid_break_mp(bifid_encipher('this is a test message for the ' \
           'keyword decipherment', 'elephant', wrap_alphabet=KeywordWrapAlphabet.from_last), \
           wordlist=['cat', 'elephant', 'kangaroo'], \
           number_of_solutions=2) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
-    [(('elephant', <KeywordWrapAlphabet.from_last: 2>), -52.834575011...), 
-    (('elephant', <KeywordWrapAlphabet.from_largest: 3>), -52.834575011...)]
+    [(('elephant', <KeywordWrapAlphabet.from_last: 2>, 0), -52.834575011...), 
+    (('elephant', <KeywordWrapAlphabet.from_largest: 3>, 0), -52.834575011...)]
     """
     with Pool() as pool:
-        helper_args = [(message, word, wrap, fitness)
+        helper_args = [(message, word, wrap, period, fitness)
                        for word in wordlist
-                       for wrap in KeywordWrapAlphabet]
+                       for wrap in KeywordWrapAlphabet
+                       for period in range(max_period+1)]
         # Gotcha: the helper function here needs to be defined at the top level
         #   (limitation of Pool.starmap)
         breaks = pool.starmap(bifid_break_worker, helper_args, chunksize)
@@ -597,13 +598,13 @@ def bifid_break_mp(message, wordlist=keywords, fitness=Pletters,
         else:
             return sorted(breaks, key=lambda k: k[1], reverse=True)[:number_of_solutions]
 
-def bifid_break_worker(message, keyword, wrap_alphabet, fitness):
-    plaintext = bifid_decipher(message, keyword, wrap_alphabet)
+def bifid_break_worker(message, keyword, wrap_alphabet, period, fitness):
+    plaintext = bifid_decipher(message, keyword, wrap_alphabet, period=period)
     fit = fitness(plaintext)
     logger.debug('Keyword break attempt using key {0} (wrap={1}) gives fit of '
                  '{2} and decrypt starting: {3}'.format(keyword, 
                      wrap_alphabet, fit, sanitise(plaintext)[:50]))
-    return (keyword, wrap_alphabet), fit
+    return (keyword, wrap_alphabet, period), fit
 
 
 def pocket_enigma_break_by_crib(message, wheel_spec, crib, crib_position):