From ad47622cc1ce7e54f588edee093bb62192d070d4 Mon Sep 17 00:00:00 2001 From: Neil Smith Date: Wed, 12 Feb 2014 21:01:24 +0000 Subject: [PATCH] Transpositions rewritten --- cipher.py | 115 +++++++++++++++++++++++++----------------------------- 1 file changed, 53 insertions(+), 62 deletions(-) diff --git a/cipher.py b/cipher.py index d261902..59eb3a6 100644 --- a/cipher.py +++ b/cipher.py @@ -1,6 +1,7 @@ import string import collections import logging +import math from itertools import zip_longest, cycle, chain from language_models import * @@ -324,46 +325,29 @@ def keyword_decipher(message, keyword, wrap_alphabet=0): cipher_translation = ''.maketrans(cipher_alphabet, string.ascii_lowercase) return message.lower().translate(cipher_translation) -def scytale_encipher(message, rows): - """Enciphers using the scytale transposition cipher. - Message is padded with spaces to allow all rows to be the same length. - >>> scytale_encipher('thequickbrownfox', 3) - 'tcnhkfeboqrxuo iw ' - >>> scytale_encipher('thequickbrownfox', 4) - 'tubnhirfecooqkwx' - >>> scytale_encipher('thequickbrownfox', 5) - 'tubn hirf ecoo qkwx ' - >>> scytale_encipher('thequickbrownfox', 6) - 'tqcrnxhukof eibwo ' - >>> scytale_encipher('thequickbrownfox', 7) - 'tqcrnx hukof eibwo ' +def vigenere_encipher(message, keyword): + """Vigenere encipher + + >>> vigenere_encipher('hello', 'abc') + 'hfnlp' """ - if len(message) % rows != 0: - message += ' '*(rows - len(message) % rows) - row_length = round(len(message) / rows) - slices = [message[i:i+row_length] - for i in range(0, len(message), row_length)] - return ''.join([''.join(r) for r in zip_longest(*slices, fillvalue='')]) + shifts = [ord(l) - ord('a') for l in sanitise(keyword)] + pairs = zip(message, cycle(shifts)) + return ''.join([caesar_encipher_letter(l, k) for l, k in pairs]) -def scytale_decipher(message, rows): - """Deciphers using the scytale transposition cipher. - Assumes the message is padded so that all rows are the same length. - - >>> scytale_decipher('tcnhkfeboqrxuo iw ', 3) - 'thequickbrownfox ' - >>> scytale_decipher('tubnhirfecooqkwx', 4) - 'thequickbrownfox' - >>> scytale_decipher('tubn hirf ecoo qkwx ', 5) - 'thequickbrownfox ' - >>> scytale_decipher('tqcrnxhukof eibwo ', 6) - 'thequickbrownfox ' - >>> scytale_decipher('tqcrnx hukof eibwo ', 7) - 'thequickbrownfox ' +def vigenere_decipher(message, keyword): + """Vigenere decipher + + >>> vigenere_decipher('hfnlp', 'abc') + 'hello' """ - cols = round(len(message) / rows) - columns = [message[i:i+rows] for i in range(0, cols * rows, rows)] - return ''.join([''.join(c) for c in zip_longest(*columns, fillvalue='')]) + shifts = [ord(l) - ord('a') for l in sanitise(keyword)] + pairs = zip(message, cycle(shifts)) + return ''.join([caesar_decipher_letter(l, k) for l, k in pairs]) + +beaufort_encipher=vigenere_decipher +beaufort_decipher=vigenere_encipher def transpositions_of(keyword): @@ -471,13 +455,6 @@ def column_transposition_decipher(message, keyword, fillvalue=' ', >>> column_transposition_decipher('hleolteher', 'clever', fillcolumnwise=False, emptycolumnwise=False) 'hellothere' """ - # >>> column_transposition_decipher('hleolteher', 'clever') - # 'hellothere' - # >>> column_transposition_decipher('hleolthre!e!', 'cleverly', fillvalue='?') - # 'hellothere!!' - # >>> column_transposition_decipher('htleehoelr', 'clever', columnwise=True) - # 'hellothere' - # """ transpositions = transpositions_of(keyword) message += pad(len(message), len(transpositions), '*') if emptycolumnwise: @@ -490,29 +467,43 @@ def column_transposition_decipher(message, keyword, fillvalue=' ', else: return ''.join(chain(*untransposed)) +def scytale_encipher(message, rows, fillvalue=' '): + """Enciphers using the scytale transposition cipher. + Message is padded with spaces to allow all rows to be the same length. -def vigenere_encipher(message, keyword): - """Vigenere encipher - - >>> vigenere_encipher('hello', 'abc') - 'hfnlp' + >>> scytale_encipher('thequickbrownfox', 3) + 'tcnhkfeboqrxuo iw ' + >>> scytale_encipher('thequickbrownfox', 4) + 'tubnhirfecooqkwx' + >>> scytale_encipher('thequickbrownfox', 5) + 'tubnhirfecooqkwx' + >>> scytale_encipher('thequickbrownfox', 6) + 'tqcrnxhukof eibwo ' + >>> scytale_encipher('thequickbrownfox', 7) + 'tqcrnxhukof eibwo ' """ - shifts = [ord(l) - ord('a') for l in sanitise(keyword)] - pairs = zip(message, cycle(shifts)) - return ''.join([caesar_encipher_letter(l, k) for l, k in pairs]) - -def vigenere_decipher(message, keyword): - """Vigenere decipher + transpositions = [i for i in range(math.ceil(len(message) / rows))] + return column_transposition_encipher(message, transpositions, + fillcolumnwise=False, emptycolumnwise=True) - >>> vigenere_decipher('hfnlp', 'abc') - 'hello' +def scytale_decipher(message, rows): + """Deciphers using the scytale transposition cipher. + Assumes the message is padded so that all rows are the same length. + + >>> scytale_decipher('tcnhkfeboqrxuo iw ', 3) + 'thequickbrownfox ' + >>> scytale_decipher('tubnhirfecooqkwx', 4) + 'thequickbrownfox' + >>> scytale_decipher('tubnhirfecooqkwx', 5) + 'thequickbrownfox' + >>> scytale_decipher('tqcrnxhukof eibwo ', 6) + 'thequickbrownfox ' + >>> scytale_decipher('tqcrnxhukof eibwo ', 7) + 'thequickbrownfox ' """ - shifts = [ord(l) - ord('a') for l in sanitise(keyword)] - pairs = zip(message, cycle(shifts)) - return ''.join([caesar_decipher_letter(l, k) for l, k in pairs]) - -beaufort_encipher=vigenere_decipher -beaufort_decipher=vigenere_encipher + transpositions = [i for i in range(math.ceil(len(message) / rows))] + return column_transposition_decipher(message, transpositions, + fillcolumnwise=False, emptycolumnwise=True) if __name__ == "__main__": -- 2.34.1