X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipher.py;fp=cipher.py;h=f29151120b411ea2c051b1059c47edc1a5ff230f;hb=159c157fee78d4370a0e603de450bd8e2def305b;hp=c5d542bb915b4cfd0775d5c100e8dce46a271d88;hpb=9c170468bbfcbe9e16b646891e396d230404bb72;p=cipher-tools.git diff --git a/cipher.py b/cipher.py index c5d542b..f291511 100644 --- a/cipher.py +++ b/cipher.py @@ -1,16 +1,10 @@ import string import collections -import logging import math +from enum import Enum from itertools import zip_longest, cycle, chain from language_models import * -logger = logging.getLogger(__name__) -logger.addHandler(logging.FileHandler('cipher.log')) -logger.setLevel(logging.WARNING) -#logger.setLevel(logging.INFO) -#logger.setLevel(logging.DEBUG) - modular_division_table = [[0]*26 for _ in range(26)] for a in range(26): @@ -33,7 +27,7 @@ def every_nth(text, n, fillvalue=''): >>> every_nth(string.ascii_lowercase, 5, fillvalue='!') ['afkpuz', 'bglqv!', 'chmrw!', 'dinsx!', 'ejoty!'] """ - split_text = [text[i:i+n] for i in range(0, len(text), n)] + split_text = chunks(text, n, fillvalue) return [''.join(l) for l in zip_longest(*split_text, fillvalue=fillvalue)] def combine_every_nth(split_text): @@ -99,7 +93,7 @@ def deduplicate(text): return list(collections.OrderedDict.fromkeys(text)) -def caesar_encipher_letter(letter, shift): +def caesar_encipher_letter(accented_letter, shift): """Encipher a letter, given a shift amount >>> caesar_encipher_letter('a', 1) @@ -118,7 +112,12 @@ def caesar_encipher_letter(letter, shift): 'y' >>> caesar_encipher_letter('a', -1) 'z' + >>> caesar_encipher_letter('A', 1) + 'B' + >>> caesar_encipher_letter('é', 1) + 'f' """ + letter = unaccent(accented_letter) if letter in string.ascii_letters: if letter in string.ascii_uppercase: alphabet_start = ord('A') @@ -150,12 +149,14 @@ def caesar_encipher(message, shift): 'cdezab' >>> caesar_encipher('ab cx yz', 2) 'cd ez ab' + >>> caesar_encipher('Héllo World!', 2) + 'Jgnnq Yqtnf!' """ enciphered = [caesar_encipher_letter(l, shift) for l in message] return ''.join(enciphered) def caesar_decipher(message, shift): - """Encipher a message with the Caesar cipher of given shift + """Decipher a message with the Caesar cipher of given shift >>> caesar_decipher('bcd', 1) 'abc' @@ -163,10 +164,12 @@ def caesar_decipher(message, shift): 'abc' >>> caesar_decipher('cd ez ab', 2) 'ab cx yz' + >>> caesar_decipher('Jgnnq Yqtnf!', 2) + 'Hello World!' """ return caesar_encipher(message, -shift) -def affine_encipher_letter(letter, multiplier=1, adder=0, one_based=True): +def affine_encipher_letter(accented_letter, multiplier=1, adder=0, one_based=True): """Encipher a letter, given a multiplier and adder >>> ''.join([affine_encipher_letter(l, 3, 5, True) \ @@ -176,6 +179,7 @@ def affine_encipher_letter(letter, multiplier=1, adder=0, one_based=True): for l in string.ascii_uppercase]) 'FILORUXADGJMPSVYBEHKNQTWZC' """ + letter = unaccent(accented_letter) if letter in string.ascii_letters: if letter in string.ascii_uppercase: alphabet_start = ord('A') @@ -208,7 +212,7 @@ def affine_decipher_letter(letter, multiplier=1, adder=0, one_based=True): if one_based: cipher_number += 1 plaintext_number = ( modular_division_table[multiplier] - [(cipher_number - adder) % 26] ) + [(cipher_number - adder) % 26]) if one_based: plaintext_number -= 1 return chr(plaintext_number % 26 + alphabet_start) else: @@ -237,28 +241,31 @@ def affine_decipher(message, multiplier=1, adder=0, one_based=True): return ''.join(enciphered) -def keyword_cipher_alphabet_of(keyword, wrap_alphabet=0): +class KeywordWrapAlphabet(Enum): + from_a = 1 + from_last = 2 + from_largest = 3 + + +def keyword_cipher_alphabet_of(keyword, wrap_alphabet=KeywordWrapAlphabet.from_a): """Find the cipher alphabet given a keyword. wrap_alphabet controls how the rest of the alphabet is added after the keyword. - 0 : from 'a' - 1 : from the last letter in the sanitised keyword - 2 : from the largest letter in the sanitised keyword >>> keyword_cipher_alphabet_of('bayes') 'bayescdfghijklmnopqrtuvwxz' - >>> keyword_cipher_alphabet_of('bayes', 0) + >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_a) 'bayescdfghijklmnopqrtuvwxz' - >>> keyword_cipher_alphabet_of('bayes', 1) + >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_last) 'bayestuvwxzcdfghijklmnopqr' - >>> keyword_cipher_alphabet_of('bayes', 2) + >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_largest) 'bayeszcdfghijklmnopqrtuvwx' """ - if wrap_alphabet == 0: + if wrap_alphabet == KeywordWrapAlphabet.from_a: cipher_alphabet = ''.join(deduplicate(sanitise(keyword) + string.ascii_lowercase)) else: - if wrap_alphabet == 1: + if wrap_alphabet == KeywordWrapAlphabet.from_last: last_keyword_letter = deduplicate(sanitise(keyword))[-1] else: last_keyword_letter = sorted(sanitise(keyword))[-1] @@ -271,7 +278,7 @@ def keyword_cipher_alphabet_of(keyword, wrap_alphabet=0): return cipher_alphabet -def keyword_encipher(message, keyword, wrap_alphabet=0): +def keyword_encipher(message, keyword, wrap_alphabet=KeywordWrapAlphabet.from_a): """Enciphers a message with a keyword substitution cipher. wrap_alphabet controls how the rest of the alphabet is added after the keyword. @@ -281,18 +288,18 @@ def keyword_encipher(message, keyword, wrap_alphabet=0): >>> keyword_encipher('test message', 'bayes') 'rsqr ksqqbds' - >>> keyword_encipher('test message', 'bayes', 0) + >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_a) 'rsqr ksqqbds' - >>> keyword_encipher('test message', 'bayes', 1) + >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_last) 'lskl dskkbus' - >>> keyword_encipher('test message', 'bayes', 2) + >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_largest) 'qspq jsppbcs' """ cipher_alphabet = keyword_cipher_alphabet_of(keyword, wrap_alphabet) cipher_translation = ''.maketrans(string.ascii_lowercase, cipher_alphabet) - return message.lower().translate(cipher_translation) + return unaccent(message).lower().translate(cipher_translation) -def keyword_decipher(message, keyword, wrap_alphabet=0): +def keyword_decipher(message, keyword, wrap_alphabet=KeywordWrapAlphabet.from_a): """Deciphers a message with a keyword substitution cipher. wrap_alphabet controls how the rest of the alphabet is added after the keyword. @@ -302,11 +309,11 @@ def keyword_decipher(message, keyword, wrap_alphabet=0): >>> keyword_decipher('rsqr ksqqbds', 'bayes') 'test message' - >>> keyword_decipher('rsqr ksqqbds', 'bayes', 0) + >>> keyword_decipher('rsqr ksqqbds', 'bayes', KeywordWrapAlphabet.from_a) 'test message' - >>> keyword_decipher('lskl dskkbus', 'bayes', 1) + >>> keyword_decipher('lskl dskkbus', 'bayes', KeywordWrapAlphabet.from_last) 'test message' - >>> keyword_decipher('qspq jsppbcs', 'bayes', 2) + >>> keyword_decipher('qspq jsppbcs', 'bayes', KeywordWrapAlphabet.from_largest) 'test message' """ cipher_alphabet = keyword_cipher_alphabet_of(keyword, wrap_alphabet) @@ -464,15 +471,18 @@ def scytale_encipher(message, rows, fillvalue=' '): >>> scytale_encipher('thequickbrownfox', 4) 'tubnhirfecooqkwx' >>> scytale_encipher('thequickbrownfox', 5) - 'tubnhirfecooqkwx' + 'tubn hirf ecoo qkwx ' >>> scytale_encipher('thequickbrownfox', 6) 'tqcrnxhukof eibwo ' >>> scytale_encipher('thequickbrownfox', 7) - 'tqcrnxhukof eibwo ' + 'tqcrnx hukof eibwo ' """ - transpositions = [i for i in range(math.ceil(len(message) / rows))] + # transpositions = [i for i in range(math.ceil(len(message) / rows))] + # return column_transposition_encipher(message, transpositions, + # fillvalue=fillvalue, fillcolumnwise=False, emptycolumnwise=True) + transpositions = [i for i in range(rows)] return column_transposition_encipher(message, transpositions, - fillcolumnwise=False, emptycolumnwise=True) + fillvalue=fillvalue, fillcolumnwise=True, emptycolumnwise=False) def scytale_decipher(message, rows): """Deciphers using the scytale transposition cipher. @@ -482,18 +492,226 @@ def scytale_decipher(message, rows): 'thequickbrownfox ' >>> scytale_decipher('tubnhirfecooqkwx', 4) 'thequickbrownfox' - >>> scytale_decipher('tubnhirfecooqkwx', 5) - 'thequickbrownfox' + >>> scytale_decipher('tubn hirf ecoo qkwx ', 5) + 'thequickbrownfox ' >>> scytale_decipher('tqcrnxhukof eibwo ', 6) 'thequickbrownfox ' - >>> scytale_decipher('tqcrnxhukof eibwo ', 7) - 'thequickbrownfox ' + >>> scytale_decipher('tqcrnx hukof eibwo ', 7) + 'thequickbrownfox ' """ - transpositions = [i for i in range(math.ceil(len(message) / rows))] + # transpositions = [i for i in range(math.ceil(len(message) / rows))] + # return column_transposition_decipher(message, transpositions, + # fillcolumnwise=False, emptycolumnwise=True) + transpositions = [i for i in range(rows)] return column_transposition_decipher(message, transpositions, - fillcolumnwise=False, emptycolumnwise=True) + fillcolumnwise=True, emptycolumnwise=False) + + +def railfence_encipher(message, height, fillvalue=' '): + """Railfence cipher + + >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 2, fillvalue='!') + 'hlohraateerishsslnpeefetotsigaleccpeselteevsmhatetiiaogicotxfretnrifneihr!' + >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 3, fillvalue='!') + 'horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihr!!lhateihsnefttiaece!' + >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 5, fillvalue='!') + 'hresleogcseeemhetaocofrnrner!!lhateihsnefttiaece!!ltvsatiigitxetifih!!oarspeslp!' + >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 10, fillvalue='!') + 'hepisehagitnr!!lernesge!!lmtocerh!!otiletap!!tseaorii!!hassfolc!!evtitffe!!rahsetec!!eixn!' + """ + sections = chunks(message, (height - 1) * 2, fillvalue=fillvalue) + # Add the top row + rows = [s[0] for s in sections] + # process the middle rows of the grid + for r in range(1, height - 1): + rows += [s[r] + s[-r] for s in sections] + # process the bottom row + rows += [s[height - 1] for s in sections] + return ''.join(rows) + +def railfence_decipher(message, height): + """Railfence decipher. Assumes the message is already the correct length. + + >>> railfence_decipher('hlohraateerishsslnpeefetotsigaleccpeselteevsmhatetiiaogicotxfretnrifneihr!', 2).strip('!') + 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' + >>> railfence_decipher('horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihr!!lhateihsnefttiaece!', 3).strip('!') + 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' + >>> railfence_decipher('hresleogcseeemhetaocofrnrner!!lhateihsnefttiaece!!ltvsatiigitxetifih!!oarspeslp!', 5).strip('!') + 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' + >>> railfence_decipher('hepisehagitnr!!lernesge!!lmtocerh!!otiletap!!tseaorii!!hassfolc!!evtitffe!!rahsetec!!eixn!', 10).strip('!') + 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' + """ + n_secs = len(message) // ((height - 1) * 2) + downrows = [message[:n_secs]] + uprows = [] + for r in range(height-2): + midrow = message[(2 * r + 1) * n_secs:(2 * r + 1) * n_secs + n_secs * 2] + downrows += [''.join([midrow[i] for i in range(0, len(midrow), 2)])] + uprows = [''.join([midrow[i] for i in range(1, len(midrow), 2)])] + uprows + downrows += [message[-n_secs:]] + rows = downrows + uprows + return ''.join(letter for section in zip(*rows) for letter in section) + + +class PocketEnigma(object): + """A pocket enigma machine + The wheel is internally represented as a 26-element list self.wheel_map, + where wheel_map[i] == j shows that the position i places on from the arrow + maps to the position j places on. + """ + def __init__(self, wheel=1, position='a'): + """initialise the pocket enigma, including which wheel to use and the + starting position of the wheel. + + The wheel is either 1 or 2 (the predefined wheels) or a list of letter + pairs. + + The position is the letter pointed to by the arrow on the wheel. + + >>> pe.wheel_map + [25, 4, 23, 10, 1, 7, 9, 5, 12, 6, 3, 17, 8, 14, 13, 21, 19, 11, 20, 16, 18, 15, 24, 2, 22, 0] + >>> pe.position + 0 + """ + self.wheel1 = [('a', 'z'), ('b', 'e'), ('c', 'x'), ('d', 'k'), + ('f', 'h'), ('g', 'j'), ('i', 'm'), ('l', 'r'), ('n', 'o'), + ('p', 'v'), ('q', 't'), ('s', 'u'), ('w', 'y')] + self.wheel2 = [('a', 'c'), ('b', 'd'), ('e', 'w'), ('f', 'i'), + ('g', 'p'), ('h', 'm'), ('j', 'k'), ('l', 'n'), ('o', 'q'), + ('r', 'z'), ('s', 'u'), ('t', 'v'), ('x', 'y')] + if wheel == 1: + self.make_wheel_map(self.wheel1) + elif wheel == 2: + self.make_wheel_map(self.wheel2) + else: + self.validate_wheel_spec(wheel) + self.make_wheel_map(wheel) + if position in string.ascii_lowercase: + self.position = ord(position) - ord('a') + else: + self.position = position + + def make_wheel_map(self, wheel_spec): + """Expands a wheel specification from a list of letter-letter pairs + into a full wheel_map. + + >>> pe.make_wheel_map(pe.wheel2) + [2, 3, 0, 1, 22, 8, 15, 12, 5, 10, 9, 13, 7, 11, 16, 6, 14, 25, 20, 21, 18, 19, 4, 24, 23, 17] + """ + self.validate_wheel_spec(wheel_spec) + self.wheel_map = [0] * 26 + for p in wheel_spec: + self.wheel_map[ord(p[0]) - ord('a')] = ord(p[1]) - ord('a') + self.wheel_map[ord(p[1]) - ord('a')] = ord(p[0]) - ord('a') + return self.wheel_map + + def validate_wheel_spec(self, wheel_spec): + """Validates that a wheel specificaiton will turn into a valid wheel + map. + + >>> pe.validate_wheel_spec([]) + Traceback (most recent call last): + ... + ValueError: Wheel specification has 0 pairs, requires 13 + >>> pe.validate_wheel_spec([('a', 'b', 'c')]*13) + Traceback (most recent call last): + ... + ValueError: Not all mappings in wheel specificationhave two elements + >>> pe.validate_wheel_spec([('a', 'b')]*13) + Traceback (most recent call last): + ... + ValueError: Wheel specification does not contain 26 letters + """ + if len(wheel_spec) != 13: + raise ValueError("Wheel specification has {} pairs, requires 13". + format(len(wheel_spec))) + for p in wheel_spec: + if len(p) != 2: + raise ValueError("Not all mappings in wheel specification" + "have two elements") + if len(set([p[0] for p in wheel_spec] + + [p[1] for p in wheel_spec])) != 26: + raise ValueError("Wheel specification does not contain 26 letters") + + def encipher_letter(self, letter): + """Enciphers a single letter, by advancing the wheel before looking up + the letter on the wheel. + + >>> pe.set_position('f') + 5 + >>> pe.encipher_letter('k') + 'h' + """ + self.advance() + return self.lookup(letter) + decipher_letter = encipher_letter + + def lookup(self, letter): + """Look up what a letter enciphers to, without turning the wheel. + + >>> pe.set_position('f') + 5 + >>> ''.join([pe.lookup(l) for l in string.ascii_lowercase]) + 'udhbfejcpgmokrliwntsayqzvx' + >>> pe.lookup('A') + '' + """ + if letter in string.ascii_lowercase: + return chr( + (self.wheel_map[(ord(letter) - ord('a') - self.position) % 26] + + self.position) % 26 + + ord('a')) + else: + return '' + + def advance(self): + """Advances the wheel one position. + + >>> pe.set_position('f') + 5 + >>> pe.advance() + 6 + """ + self.position = (self.position + 1) % 26 + return self.position + + def encipher(self, message, starting_position=None): + """Enciphers a whole message. + + >>> pe.set_position('f') + 5 + >>> pe.encipher('helloworld') + 'kjsglcjoqc' + >>> pe.set_position('f') + 5 + >>> pe.encipher('kjsglcjoqc') + 'helloworld' + >>> pe.encipher('helloworld', starting_position = 'x') + 'egrekthnnf' + """ + if starting_position: + self.set_position(starting_position) + transformed = '' + for l in message: + transformed += self.encipher_letter(l) + return transformed + decipher = encipher + + def set_position(self, position): + """Sets the position of the wheel, by specifying the letter the arrow + points to. + + >>> pe.set_position('a') + 0 + >>> pe.set_position('m') + 12 + >>> pe.set_position('z') + 25 + """ + self.position = ord(position) - ord('a') + return self.position if __name__ == "__main__": import doctest - doctest.testmod() + doctest.testmod(extraglobs={'pe': PocketEnigma(1, 'a')})