X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipher.py;fp=cipher.py;h=0000000000000000000000000000000000000000;hb=92ae3192f1ac20bfefacbefa7c2d68f843553e80;hp=266237a65a70b070e2ea8bc41d49f273477eda2c;hpb=20aff345391c6ae2d00a55c586fda31f6f4315d5;p=cipher-training.git diff --git a/cipher.py b/cipher.py deleted file mode 100644 index 266237a..0000000 --- a/cipher.py +++ /dev/null @@ -1,1056 +0,0 @@ -import string -import collections -import math -from enum import Enum -from itertools import zip_longest, cycle, chain, count -import numpy as np -from numpy import matrix -from numpy import linalg -from language_models import * - - -modular_division_table = [[0]*26 for _ in range(26)] -for a in range(26): - for b in range(26): - c = (a * b) % 26 - modular_division_table[b][c] = a - - -def every_nth(text, n, fillvalue=''): - """Returns n strings, each of which consists of every nth character, - starting with the 0th, 1st, 2nd, ... (n-1)th character - - >>> every_nth(string.ascii_lowercase, 5) - ['afkpuz', 'bglqv', 'chmrw', 'dinsx', 'ejoty'] - >>> every_nth(string.ascii_lowercase, 1) - ['abcdefghijklmnopqrstuvwxyz'] - >>> every_nth(string.ascii_lowercase, 26) # doctest: +NORMALIZE_WHITESPACE - ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', - 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'] - >>> every_nth(string.ascii_lowercase, 5, fillvalue='!') - ['afkpuz', 'bglqv!', 'chmrw!', 'dinsx!', 'ejoty!'] - """ - split_text = chunks(text, n, fillvalue) - return [''.join(l) for l in zip_longest(*split_text, fillvalue=fillvalue)] - -def combine_every_nth(split_text): - """Reforms a text split into every_nth strings - - >>> combine_every_nth(every_nth(string.ascii_lowercase, 5)) - 'abcdefghijklmnopqrstuvwxyz' - >>> combine_every_nth(every_nth(string.ascii_lowercase, 1)) - 'abcdefghijklmnopqrstuvwxyz' - >>> combine_every_nth(every_nth(string.ascii_lowercase, 26)) - 'abcdefghijklmnopqrstuvwxyz' - """ - return ''.join([''.join(l) - for l in zip_longest(*split_text, fillvalue='')]) - -def chunks(text, n, fillvalue=None): - """Split a text into chunks of n characters - - >>> chunks('abcdefghi', 3) - ['abc', 'def', 'ghi'] - >>> chunks('abcdefghi', 4) - ['abcd', 'efgh', 'i'] - >>> chunks('abcdefghi', 4, fillvalue='!') - ['abcd', 'efgh', 'i!!!'] - """ - if fillvalue: - padding = fillvalue[0] * (n - len(text) % n) - else: - padding = '' - return [(text+padding)[i:i+n] for i in range(0, len(text), n)] - -def transpose(items, transposition): - """Moves items around according to the given transposition - - >>> transpose(['a', 'b', 'c', 'd'], (0,1,2,3)) - ['a', 'b', 'c', 'd'] - >>> transpose(['a', 'b', 'c', 'd'], (3,1,2,0)) - ['d', 'b', 'c', 'a'] - >>> transpose([10,11,12,13,14,15], (3,2,4,1,5,0)) - [13, 12, 14, 11, 15, 10] - """ - transposed = [''] * len(transposition) - for p, t in enumerate(transposition): - transposed[p] = items[t] - return transposed - -def untranspose(items, transposition): - """Undoes a transpose - - >>> untranspose(['a', 'b', 'c', 'd'], [0,1,2,3]) - ['a', 'b', 'c', 'd'] - >>> untranspose(['d', 'b', 'c', 'a'], [3,1,2,0]) - ['a', 'b', 'c', 'd'] - >>> untranspose([13, 12, 14, 11, 15, 10], [3,2,4,1,5,0]) - [10, 11, 12, 13, 14, 15] - """ - transposed = [''] * len(transposition) - for p, t in enumerate(transposition): - transposed[t] = items[p] - return transposed - -def deduplicate(text): - return list(collections.OrderedDict.fromkeys(text)) - - -def caesar_encipher_letter(accented_letter, shift): - """Encipher a letter, given a shift amount - - >>> caesar_encipher_letter('a', 1) - 'b' - >>> caesar_encipher_letter('a', 2) - 'c' - >>> caesar_encipher_letter('b', 2) - 'd' - >>> caesar_encipher_letter('x', 2) - 'z' - >>> caesar_encipher_letter('y', 2) - 'a' - >>> caesar_encipher_letter('z', 2) - 'b' - >>> caesar_encipher_letter('z', -1) - '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') - else: - alphabet_start = ord('a') - return chr(((ord(letter) - alphabet_start + shift) % 26) + - alphabet_start) - else: - return letter - -def caesar_decipher_letter(letter, shift): - """Decipher a letter, given a shift amount - - >>> caesar_decipher_letter('b', 1) - 'a' - >>> caesar_decipher_letter('b', 2) - 'z' - """ - return caesar_encipher_letter(letter, -shift) - -def caesar_encipher(message, shift): - """Encipher a message with the Caesar cipher of given shift - - >>> caesar_encipher('abc', 1) - 'bcd' - >>> caesar_encipher('abc', 2) - 'cde' - >>> caesar_encipher('abcxyz', 2) - '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): - """Decipher a message with the Caesar cipher of given shift - - >>> caesar_decipher('bcd', 1) - 'abc' - >>> caesar_decipher('cde', 2) - '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(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) \ - for l in string.ascii_uppercase]) - 'HKNQTWZCFILORUXADGJMPSVYBE' - >>> ''.join([affine_encipher_letter(l, 3, 5, False) \ - 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') - else: - alphabet_start = ord('a') - letter_number = ord(letter) - alphabet_start - if one_based: letter_number += 1 - cipher_number = (letter_number * multiplier + adder) % 26 - if one_based: cipher_number -= 1 - return chr(cipher_number % 26 + alphabet_start) - else: - return letter - -def affine_decipher_letter(letter, multiplier=1, adder=0, one_based=True): - """Encipher a letter, given a multiplier and adder - - >>> ''.join([affine_decipher_letter(l, 3, 5, True) \ - for l in 'HKNQTWZCFILORUXADGJMPSVYBE']) - 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' - >>> ''.join([affine_decipher_letter(l, 3, 5, False) \ - for l in 'FILORUXADGJMPSVYBEHKNQTWZC']) - 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' - """ - if letter in string.ascii_letters: - if letter in string.ascii_uppercase: - alphabet_start = ord('A') - else: - 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]) - if one_based: plaintext_number -= 1 - return chr(plaintext_number % 26 + alphabet_start) - else: - return letter - -def affine_encipher(message, multiplier=1, adder=0, one_based=True): - """Encipher a message - - >>> affine_encipher('hours passed during which jerico tried every ' \ - 'trick he could think of', 15, 22, True) - 'lmyfu bkuusd dyfaxw claol psfaom jfasd snsfg jfaoe ls omytd jlaxe mh' - """ - enciphered = [affine_encipher_letter(l, multiplier, adder, one_based) - for l in message] - return ''.join(enciphered) - -def affine_decipher(message, multiplier=1, adder=0, one_based=True): - """Decipher a message - - >>> affine_decipher('lmyfu bkuusd dyfaxw claol psfaom jfasd snsfg ' \ - 'jfaoe ls omytd jlaxe mh', 15, 22, True) - 'hours passed during which jerico tried every trick he could think of' - """ - enciphered = [affine_decipher_letter(l, multiplier, adder, one_based) - for l in message] - return ''.join(enciphered) - - -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. - - >>> keyword_cipher_alphabet_of('bayes') - 'bayescdfghijklmnopqrtuvwxz' - >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_a) - 'bayescdfghijklmnopqrtuvwxz' - >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_last) - 'bayestuvwxzcdfghijklmnopqr' - >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_largest) - 'bayeszcdfghijklmnopqrtuvwx' - """ - if wrap_alphabet == KeywordWrapAlphabet.from_a: - cipher_alphabet = ''.join(deduplicate(sanitise(keyword) + - string.ascii_lowercase)) - else: - if wrap_alphabet == KeywordWrapAlphabet.from_last: - last_keyword_letter = deduplicate(sanitise(keyword))[-1] - else: - last_keyword_letter = sorted(sanitise(keyword))[-1] - last_keyword_position = string.ascii_lowercase.find( - last_keyword_letter) + 1 - cipher_alphabet = ''.join( - deduplicate(sanitise(keyword) + - string.ascii_lowercase[last_keyword_position:] + - string.ascii_lowercase)) - return cipher_alphabet - - -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. - 0 : from 'a' - 1 : from the last letter in the sanitised keyword - 2 : from the largest letter in the sanitised keyword - - >>> keyword_encipher('test message', 'bayes') - 'rsqr ksqqbds' - >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_a) - 'rsqr ksqqbds' - >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_last) - 'lskl dskkbus' - >>> 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 unaccent(message).lower().translate(cipher_translation) - -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. - 0 : from 'a' - 1 : from the last letter in the sanitised keyword - 2 : from the largest letter in the sanitised keyword - - >>> keyword_decipher('rsqr ksqqbds', 'bayes') - 'test message' - >>> keyword_decipher('rsqr ksqqbds', 'bayes', KeywordWrapAlphabet.from_a) - 'test message' - >>> keyword_decipher('lskl dskkbus', 'bayes', KeywordWrapAlphabet.from_last) - 'test message' - >>> keyword_decipher('qspq jsppbcs', 'bayes', KeywordWrapAlphabet.from_largest) - 'test message' - """ - cipher_alphabet = keyword_cipher_alphabet_of(keyword, wrap_alphabet) - cipher_translation = ''.maketrans(cipher_alphabet, string.ascii_lowercase) - return message.lower().translate(cipher_translation) - - -def vigenere_encipher(message, keyword): - """Vigenere encipher - - >>> vigenere_encipher('hello', 'abc') - 'hfnlp' - """ - 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 - - >>> vigenere_decipher('hfnlp', 'abc') - 'hello' - """ - 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): - """Finds the transpostions given by a keyword. For instance, the keyword - 'clever' rearranges to 'celrv', so the first column (0) stays first, the - second column (1) moves to third, the third column (2) moves to second, - and so on. - - If passed a tuple, assume it's already a transposition and just return it. - - >>> transpositions_of('clever') - (0, 2, 1, 4, 3) - >>> transpositions_of('fred') - (3, 2, 0, 1) - >>> transpositions_of((3, 2, 0, 1)) - (3, 2, 0, 1) - """ - if isinstance(keyword, tuple): - return keyword - else: - key = deduplicate(keyword) - 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=' ', - fillcolumnwise=False, - emptycolumnwise=False): - """Enciphers using the column transposition cipher. - Message is padded to allow all rows to be the same length. - - >>> column_transposition_encipher('hellothere', 'abcdef', fillcolumnwise=True) - 'hlohr eltee ' - >>> column_transposition_encipher('hellothere', 'abcdef', fillcolumnwise=True, emptycolumnwise=True) - 'hellothere ' - >>> column_transposition_encipher('hellothere', 'abcdef') - 'hellothere ' - >>> column_transposition_encipher('hellothere', 'abcde') - 'hellothere' - >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=True) - 'hellothere' - >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=False) - 'hlohreltee' - >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=True) - 'htehlelroe' - >>> column_transposition_encipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=False) - 'hellothere' - >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=True, emptycolumnwise=True) - 'heotllrehe' - >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=True, emptycolumnwise=False) - 'holrhetlee' - >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=False, emptycolumnwise=True) - 'htleehoelr' - >>> column_transposition_encipher('hellothere', 'clever', fillcolumnwise=False, emptycolumnwise=False) - 'hleolteher' - >>> column_transposition_encipher('hellothere', 'cleverly') - 'hleolthre e ' - >>> column_transposition_encipher('hellothere', 'cleverly', fillvalue='!') - 'hleolthre!e!' - >>> column_transposition_encipher('hellothere', 'cleverly', fillvalue=lambda: '*') - 'hleolthre*e*' - """ - transpositions = transpositions_of(keyword) - message += pad(len(message), len(transpositions), fillvalue) - if fillcolumnwise: - rows = every_nth(message, len(message) // len(transpositions)) - else: - rows = chunks(message, len(transpositions)) - transposed = [transpose(r, transpositions) for r in rows] - if emptycolumnwise: - return combine_every_nth(transposed) - else: - return ''.join(chain(*transposed)) - -def column_transposition_decipher(message, keyword, fillvalue=' ', - fillcolumnwise=False, - emptycolumnwise=False): - """Deciphers using the column transposition cipher. - Message is padded to allow all rows to be the same length. - - >>> column_transposition_decipher('hellothere', 'abcde', fillcolumnwise=True, emptycolumnwise=True) - 'hellothere' - >>> column_transposition_decipher('hlohreltee', 'abcde', fillcolumnwise=True, emptycolumnwise=False) - 'hellothere' - >>> column_transposition_decipher('htehlelroe', 'abcde', fillcolumnwise=False, emptycolumnwise=True) - 'hellothere' - >>> column_transposition_decipher('hellothere', 'abcde', fillcolumnwise=False, emptycolumnwise=False) - 'hellothere' - >>> column_transposition_decipher('heotllrehe', 'clever', fillcolumnwise=True, emptycolumnwise=True) - 'hellothere' - >>> column_transposition_decipher('holrhetlee', 'clever', fillcolumnwise=True, emptycolumnwise=False) - 'hellothere' - >>> column_transposition_decipher('htleehoelr', 'clever', fillcolumnwise=False, emptycolumnwise=True) - 'hellothere' - >>> column_transposition_decipher('hleolteher', 'clever', fillcolumnwise=False, emptycolumnwise=False) - 'hellothere' - """ - transpositions = transpositions_of(keyword) - message += pad(len(message), len(transpositions), fillvalue) - if emptycolumnwise: - rows = every_nth(message, len(message) // len(transpositions)) - else: - rows = chunks(message, len(transpositions)) - untransposed = [untranspose(r, transpositions) for r in rows] - if fillcolumnwise: - return combine_every_nth(untransposed) - 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. - - >>> 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 ' - """ - # 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, - fillvalue=fillvalue, fillcolumnwise=True, emptycolumnwise=False) - -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 ' - """ - # 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=True, emptycolumnwise=False) - - -def railfence_encipher(message, height, fillvalue=''): - """Railfence cipher. - Works by splitting the text into sections, then reading across them to - generate the rows in the cipher. The rows are then combined to form the - ciphertext. - - Example: the plaintext "hellotherefriends", with a height of four, written - out in the railfence as - h h i - etere* - lorfns - l e d - (with the * showing the one character to finish the last section). - Each 'section' is two columns, but unfolded. In the example, the first - section is 'hellot'. - - >>> 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!' - >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 3) - 'horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihrlhateihsnefttiaece' - >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 5) - 'hresleogcseeemhetaocofrnrnerlhateihsnefttiaeceltvsatiigitxetifihoarspeslp' - >>> railfence_encipher('hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers', 7) - 'haspolsevsetgifrifrlatihnettaeelemtiocxernhorersleesgcptehaiaottneihesfic' - """ - sections = chunks(message, (height - 1) * 2, fillvalue=fillvalue) - n_sections = len(sections) - # Add the top row - rows = [''.join([s[0] for s in sections])] - # process the middle rows of the grid - for r in range(1, height-1): - rows += [''.join([s[r:r+1] + s[height*2-r-2:height*2-r-1] for s in sections])] - # process the bottom row - rows += [''.join([s[height - 1:height] for s in sections])] - # rows += [' '.join([s[height - 1] for s in sections])] - return ''.join(rows) - -def railfence_decipher(message, height, fillvalue=''): - """Railfence decipher. - Works by reconstructing the grid used to generate the ciphertext, then - unfolding the sections so the text can be concatenated together. - - Example: given the ciphertext 'hhieterelorfnsled' and a height of 4, first - work out that the second row has a character missing, find the rows of the - grid, then split the section into its two columns. - - 'hhieterelorfnsled' is split into - h h i - etere - lorfns - l e d - (spaces added for clarity), which is stored in 'rows'. This is then split - into 'down_rows' and 'up_rows': - - down_rows: - hhi - eee - lrn - led - - up_rows: - tr - ofs - - These are then zipped together (after the up_rows are reversed) to recover - the plaintext. - - Most of the procedure is about finding the correct lengths for each row then - splitting the ciphertext into those rows. - - >>> 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' - >>> railfence_decipher('horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihrlhateihsnefttiaece', 3) - 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' - >>> railfence_decipher('hresleogcseeemhetaocofrnrnerlhateihsnefttiaeceltvsatiigitxetifihoarspeslp', 5) - 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' - >>> railfence_decipher('haspolsevsetgifrifrlatihnettaeelemtiocxernhorersleesgcptehaiaottneihesfic', 7) - 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers' - """ - # find the number and size of the sections, including how many characters - # are missing for a full grid - n_sections = math.ceil(len(message) / ((height - 1) * 2)) - padding_to_add = n_sections * (height - 1) * 2 - len(message) - # row_lengths are for the both up rows and down rows - row_lengths = [n_sections] * (height - 1) * 2 - for i in range((height - 1) * 2 - 1, (height - 1) * 2 - (padding_to_add + 1), -1): - row_lengths[i] -= 1 - # folded_rows are the combined row lengths in the middle of the railfence - folded_row_lengths = [row_lengths[0]] - for i in range(1, height-1): - folded_row_lengths += [row_lengths[i] + row_lengths[-i]] - folded_row_lengths += [row_lengths[height - 1]] - # find the rows that form the railfence grid - rows = [] - row_start = 0 - for i in folded_row_lengths: - rows += [message[row_start:row_start + i]] - row_start += i - # split the rows into the 'down_rows' (those that form the first column of - # a section) and the 'up_rows' (those that ofrm the second column of a - # section). - down_rows = [rows[0]] - up_rows = [] - for i in range(1, height-1): - down_rows += [''.join([c for n, c in enumerate(rows[i]) if n % 2 == 0])] - up_rows += [''.join([c for n, c in enumerate(rows[i]) if n % 2 == 1])] - down_rows += [rows[-1]] - up_rows.reverse() - return ''.join(c for r in zip_longest(*(down_rows + up_rows), fillvalue='') for c in r) - -def make_cadenus_keycolumn(doubled_letters = 'vw', start='a', reverse=False): - """Makes the key column for a Cadenus cipher (the column down between the - rows of letters) - - >>> make_cadenus_keycolumn()['a'] - 0 - >>> make_cadenus_keycolumn()['b'] - 1 - >>> make_cadenus_keycolumn()['c'] - 2 - >>> make_cadenus_keycolumn()['v'] - 21 - >>> make_cadenus_keycolumn()['w'] - 21 - >>> make_cadenus_keycolumn()['z'] - 24 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['a'] - 1 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['b'] - 0 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['c'] - 24 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['i'] - 18 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['j'] - 18 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['v'] - 6 - >>> make_cadenus_keycolumn(doubled_letters='ij', start='b', reverse=True)['z'] - 2 - """ - index_to_remove = string.ascii_lowercase.find(doubled_letters[0]) - short_alphabet = string.ascii_lowercase[:index_to_remove] + string.ascii_lowercase[index_to_remove+1:] - if reverse: - short_alphabet = ''.join(reversed(short_alphabet)) - start_pos = short_alphabet.find(start) - rotated_alphabet = short_alphabet[start_pos:] + short_alphabet[:start_pos] - keycolumn = {l: i for i, l in enumerate(rotated_alphabet)} - keycolumn[doubled_letters[0]] = keycolumn[doubled_letters[1]] - return keycolumn - -def cadenus_encipher(message, keyword, keycolumn, fillvalue='a'): - """Encipher with the Cadenus cipher - - >>> cadenus_encipher(sanitise('Whoever has made a voyage up the Hudson ' \ - 'must remember the Kaatskill mountains. ' \ - 'They are a dismembered branch of the great'), \ - 'wink', \ - make_cadenus_keycolumn(doubled_letters='vw', start='a', reverse=True)) - 'antodeleeeuhrsidrbhmhdrrhnimefmthgeaetakseomehetyaasuvoyegrastmmuuaeenabbtpchehtarorikswosmvaleatned' - >>> cadenus_encipher(sanitise('a severe limitation on the usefulness of ' \ - 'the cadenus is that every message must be ' \ - 'a multiple of twenty-five letters long'), \ - 'easy', \ - make_cadenus_keycolumn(doubled_letters='vw', start='a', reverse=True)) - 'systretomtattlusoatleeesfiyheasdfnmschbhneuvsnpmtofarenuseieeieltarlmentieetogevesitfaisltngeeuvowul' - """ - rows = chunks(message, len(message) // 25, fillvalue=fillvalue) - columns = zip(*rows) - rotated_columns = [col[start:] + col[:start] for start, col in zip([keycolumn[l] for l in keyword], columns)] - rotated_rows = zip(*rotated_columns) - transpositions = transpositions_of(keyword) - transposed = [transpose(r, transpositions) for r in rotated_rows] - return ''.join(chain(*transposed)) - -def cadenus_decipher(message, keyword, keycolumn, fillvalue='a'): - """ - >>> cadenus_decipher('antodeleeeuhrsidrbhmhdrrhnimefmthgeaetakseomehetyaa' \ - 'suvoyegrastmmuuaeenabbtpchehtarorikswosmvaleatned', \ - 'wink', \ - make_cadenus_keycolumn(reverse=True)) - 'whoeverhasmadeavoyageupthehudsonmustrememberthekaatskillmountainstheyareadismemberedbranchofthegreat' - >>> cadenus_decipher('systretomtattlusoatleeesfiyheasdfnmschbhneuvsnpmtof' \ - 'arenuseieeieltarlmentieetogevesitfaisltngeeuvowul', \ - 'easy', \ - make_cadenus_keycolumn(reverse=True)) - 'aseverelimitationontheusefulnessofthecadenusisthateverymessagemustbeamultipleoftwentyfiveletterslong' - """ - rows = chunks(message, len(message) // 25, fillvalue=fillvalue) - transpositions = transpositions_of(keyword) - untransposed_rows = [untranspose(r, transpositions) for r in rows] - columns = zip(*untransposed_rows) - rotated_columns = [col[-start:] + col[:-start] for start, col in zip([keycolumn[l] for l in keyword], columns)] - rotated_rows = zip(*rotated_columns) - # return rotated_columns - return ''.join(chain(*rotated_rows)) - - -def hill_encipher(matrix, message_letters, fillvalue='a'): - """Hill cipher - - >>> hill_encipher(np.matrix([[7,8], [11,11]]), 'hellothere') - 'drjiqzdrvx' - >>> hill_encipher(np.matrix([[6, 24, 1], [13, 16, 10], [20, 17, 15]]), \ - 'hello there') - 'tfjflpznvyac' - """ - n = len(matrix) - sanitised_message = sanitise(message_letters) - if len(sanitised_message) % n != 0: - padding = fillvalue[0] * (n - len(sanitised_message) % n) - else: - padding = '' - message = [ord(c) - ord('a') for c in sanitised_message + padding] - message_chunks = [message[i:i+n] for i in range(0, len(message), n)] - # message_chunks = chunks(message, len(matrix), fillvalue=None) - enciphered_chunks = [((matrix * np.matrix(c).T).T).tolist()[0] - for c in message_chunks] - return ''.join([chr(int(round(l)) % 26 + ord('a')) - for l in sum(enciphered_chunks, [])]) - -def hill_decipher(matrix, message, fillvalue='a'): - """Hill cipher - - >>> hill_decipher(np.matrix([[7,8], [11,11]]), 'drjiqzdrvx') - 'hellothere' - >>> hill_decipher(np.matrix([[6, 24, 1], [13, 16, 10], [20, 17, 15]]), \ - 'tfjflpznvyac') - 'hellothereaa' - """ - adjoint = linalg.det(matrix)*linalg.inv(matrix) - inverse_determinant = modular_division_table[int(round(linalg.det(matrix))) % 26][1] - inverse_matrix = (inverse_determinant * adjoint) % 26 - return hill_encipher(inverse_matrix, message, fillvalue) - - -# Where each piece of text ends up in the AMSCO transpositon cipher. -# 'index' shows where the slice appears in the plaintext, with the slice -# from 'start' to 'end' -AmscoSlice = collections.namedtuple('AmscoSlice', ['index', 'start', 'end']) - -class AmscoFillStyle(Enum): - continuous = 1 - same_each_row = 2 - reverse_each_row = 3 - -def amsco_transposition_positions(message, keyword, - fillpattern=(1, 2), - fillstyle=AmscoFillStyle.continuous, - fillcolumnwise=False, - emptycolumnwise=True): - """Creates the grid for the AMSCO transposition cipher. Each element in the - grid shows the index of that slice and the start and end positions of the - plaintext that go to make it up. - - >>> amsco_transposition_positions(string.ascii_lowercase, 'freddy', \ - fillpattern=(1, 2)) # doctest: +NORMALIZE_WHITESPACE - [[AmscoSlice(index=3, start=4, end=6), - AmscoSlice(index=2, start=3, end=4), - AmscoSlice(index=0, start=0, end=1), - AmscoSlice(index=1, start=1, end=3), - AmscoSlice(index=4, start=6, end=7)], - [AmscoSlice(index=8, start=12, end=13), - AmscoSlice(index=7, start=10, end=12), - AmscoSlice(index=5, start=7, end=9), - AmscoSlice(index=6, start=9, end=10), - AmscoSlice(index=9, start=13, end=15)], - [AmscoSlice(index=13, start=19, end=21), - AmscoSlice(index=12, start=18, end=19), - AmscoSlice(index=10, start=15, end=16), - AmscoSlice(index=11, start=16, end=18), - AmscoSlice(index=14, start=21, end=22)], - [AmscoSlice(index=18, start=27, end=28), - AmscoSlice(index=17, start=25, end=27), - AmscoSlice(index=15, start=22, end=24), - AmscoSlice(index=16, start=24, end=25), - AmscoSlice(index=19, start=28, end=30)]] - """ - transpositions = transpositions_of(keyword) - fill_iterator = cycle(fillpattern) - indices = count() - message_length = len(message) - - current_position = 0 - grid = [] - current_fillpattern = fillpattern - while current_position < message_length: - row = [] - if fillstyle == AmscoFillStyle.same_each_row: - fill_iterator = cycle(fillpattern) - if fillstyle == AmscoFillStyle.reverse_each_row: - fill_iterator = cycle(current_fillpattern) - for _ in range(len(transpositions)): - index = next(indices) - gap = next(fill_iterator) - row += [AmscoSlice(index, current_position, current_position + gap)] - current_position += gap - grid += [row] - if fillstyle == AmscoFillStyle.reverse_each_row: - current_fillpattern = list(reversed(current_fillpattern)) - return [transpose(r, transpositions) for r in grid] - -def amsco_transposition_encipher(message, keyword, - fillpattern=(1,2), fillstyle=AmscoFillStyle.reverse_each_row): - """AMSCO transposition encipher. - - >>> amsco_transposition_encipher('hellothere', 'abc', fillpattern=(1, 2)) - 'hoteelhler' - >>> amsco_transposition_encipher('hellothere', 'abc', fillpattern=(2, 1)) - 'hetelhelor' - >>> amsco_transposition_encipher('hellothere', 'acb', fillpattern=(1, 2)) - 'hotelerelh' - >>> amsco_transposition_encipher('hellothere', 'acb', fillpattern=(2, 1)) - 'hetelorlhe' - >>> amsco_transposition_encipher('hereissometexttoencipher', 'encode') - 'etecstthhomoerereenisxip' - >>> amsco_transposition_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 2)) - 'hetcsoeisterereipexthomn' - >>> amsco_transposition_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 2), fillstyle=AmscoFillStyle.continuous) - 'hecsoisttererteipexhomen' - >>> amsco_transposition_encipher('hereissometexttoencipher', 'cipher', fillpattern=(2, 1)) - 'heecisoosttrrtepeixhemen' - >>> amsco_transposition_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 3, 2)) - 'hxtomephescieretoeisnter' - >>> amsco_transposition_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 3, 2), fillstyle=AmscoFillStyle.continuous) - 'hxomeiphscerettoisenteer' - """ - grid = amsco_transposition_positions(message, keyword, - fillpattern=fillpattern, fillstyle=fillstyle) - ct_as_grid = [[message[s.start:s.end] for s in r] for r in grid] - return combine_every_nth(ct_as_grid) - - -def amsco_transposition_decipher(message, keyword, - fillpattern=(1,2), fillstyle=AmscoFillStyle.reverse_each_row): - """AMSCO transposition decipher - - >>> amsco_transposition_decipher('hoteelhler', 'abc', fillpattern=(1, 2)) - 'hellothere' - >>> amsco_transposition_decipher('hetelhelor', 'abc', fillpattern=(2, 1)) - 'hellothere' - >>> amsco_transposition_decipher('hotelerelh', 'acb', fillpattern=(1, 2)) - 'hellothere' - >>> amsco_transposition_decipher('hetelorlhe', 'acb', fillpattern=(2, 1)) - 'hellothere' - >>> amsco_transposition_decipher('etecstthhomoerereenisxip', 'encode') - 'hereissometexttoencipher' - >>> amsco_transposition_decipher('hetcsoeisterereipexthomn', 'cipher', fillpattern=(1, 2)) - 'hereissometexttoencipher' - >>> amsco_transposition_decipher('hecsoisttererteipexhomen', 'cipher', fillpattern=(1, 2), fillstyle=AmscoFillStyle.continuous) - 'hereissometexttoencipher' - >>> amsco_transposition_decipher('heecisoosttrrtepeixhemen', 'cipher', fillpattern=(2, 1)) - 'hereissometexttoencipher' - >>> amsco_transposition_decipher('hxtomephescieretoeisnter', 'cipher', fillpattern=(1, 3, 2)) - 'hereissometexttoencipher' - >>> amsco_transposition_decipher('hxomeiphscerettoisenteer', 'cipher', fillpattern=(1, 3, 2), fillstyle=AmscoFillStyle.continuous) - 'hereissometexttoencipher' - """ - - grid = amsco_transposition_positions(message, keyword, - fillpattern=fillpattern, fillstyle=fillstyle) - transposed_sections = [s for c in [l for l in zip(*grid)] for s in c] - plaintext_list = [''] * len(transposed_sections) - current_pos = 0 - for slice in transposed_sections: - plaintext_list[slice.index] = message[current_pos:current_pos-slice.start+slice.end][:len(message[slice.start:slice.end])] - current_pos += len(message[slice.start:slice.end]) - return ''.join(plaintext_list) - - -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(extraglobs={'pe': PocketEnigma(1, 'a')})