import string
import collections
import logging
-from itertools import zip_longest, cycle
+from itertools import zip_longest, cycle, chain
+from counts import *
logger = logging.getLogger(__name__)
#logger.setLevel(logging.DEBUG)
+english_counts = collections.defaultdict(int)
+with open('count_1l.txt', 'r') as f:
+ for line in f:
+ (letter, count) = line.split("\t")
+ english_counts[letter] = int(count)
+normalised_english_counts = norms.normalise(english_counts)
+
+choices, weights = zip(*weighted_choices)
+cumdist = list(itertools.accumulate(weights))
+x = random.random() * cumdist[-1]
+choices[bisect.bisect(cumdist, x)]
+
+
modular_division_table = [[0]*26 for x in range(26)]
for a in range(26):
for b in range(26):
alphabet_start = ord('a')
cipher_number = ord(letter) - alphabet_start
if one_based: cipher_number += 1
- plaintext_number = ( modular_division_table[multiplier]
- [(cipher_number - adder) % 26] )
+ plaintext_number = (
+ modular_division_table[multiplier]
+ [(cipher_number - adder) % 26] )
if one_based: plaintext_number -= 1
return chr(plaintext_number % 26 + alphabet_start)
else:
transpositions = tuple(key.index(l) for l in sorted(key))
return transpositions
+def pad(message_len, group_len, fillvalue):
+ padding_length = group_len - message_len % group_len
+ if padding_length == group_len: padding_length = 0
+ padding = ''
+ for i in range(padding_length):
+ if callable(fillvalue):
+ padding += fillvalue()
+ else:
+ padding += fillvalue
+ return padding
+
def column_transposition_encipher(message, keyword, fillvalue=' ',
- columnwise=False):
+ fillcolumnwise=False,
+ emptycolumnwise=False):
"""Enciphers using the column transposition cipher.
Message is padded to allow all rows to be the same length.
'htleehoelr'
"""
transpositions = transpositions_of(keyword)
+ message += pad(len(message), len(transpositions), fillvalue)
+ if fillcolumnwise:
+ rows = every_nth(message, len(transpositions))
+ else:
+ rows = chunks(mesage, len(transpositions))
columns = every_nth(message, len(transpositions), fillvalue=fillvalue)
- transposed_columns = transpose(columns, transpositions)
- if columnwise:
- return ''.join(transposed_columns)
+ transposed = [transpose(r, transpositions) for r in rows]
+ if emptycolumnwise:
+ return combine_every_nth(transposed)
else:
- return combine_every_nth(transposed_columns)
+ return ''.join(chain(*transposed))
def column_transposition_decipher(message, keyword, fillvalue=' ',
columnwise=False):