+"""A set of ciphers with implementations for both enciphering and deciphering
+them. See cipherbreak for automatic breaking of these ciphers
+"""
+
import string
import collections
-import math
from enum import Enum
from itertools import zip_longest, cycle, chain
-from language_models import *
+from language_models import unaccent, sanitise
modular_division_table = [[0]*26 for _ in range(26)]
def every_nth(text, n, fillvalue=''):
- """Returns n strings, each of which consists of every nth character,
+ """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',
+ ['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!']
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))
>>> combine_every_nth(every_nth(string.ascii_lowercase, 26))
'abcdefghijklmnopqrstuvwxyz'
"""
- return ''.join([''.join(l)
+ return ''.join([''.join(l)
for l in zip_longest(*split_text, fillvalue='')])
def chunks(text, n, fillvalue=None):
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))
"""
transposed = [''] * len(transposition)
for p, t in enumerate(transposition):
- transposed[p] = items[t]
+ 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])
"""
transposed = [''] * len(transposition)
for p, t in enumerate(transposition):
- transposed[t] = items[p]
+ transposed[t] = items[p]
return transposed
def deduplicate(text):
+ """If a string contains duplicate letters, remove all but the first. Retain
+ the order of the letters.
+
+ >>> deduplicate('cat')
+ ['c', 'a', 't']
+ >>> deduplicate('happy')
+ ['h', 'a', 'p', 'y']
+ >>> deduplicate('cattca')
+ ['c', 'a', 't']
+ """
return list(collections.OrderedDict.fromkeys(text))
alphabet_start = ord('A')
else:
alphabet_start = ord('a')
- return chr(((ord(letter) - alphabet_start + shift) % 26) +
+ 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)
def caesar_encipher(message, shift):
"""Encipher a message with the Caesar cipher of given shift
-
+
>>> caesar_encipher('abc', 1)
'bcd'
>>> caesar_encipher('abc', 2)
def caesar_decipher(message, shift):
"""Decipher a message with the Caesar cipher of given shift
-
+
>>> caesar_decipher('bcd', 1)
'abc'
>>> caesar_decipher('cde', 2)
"""
return caesar_encipher(message, -shift)
-def affine_encipher_letter(accented_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) \
for l in string.ascii_uppercase])
'HKNQTWZCFILORUXADGJMPSVYBE'
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'
alphabet_start = ord('a')
cipher_number = ord(letter) - alphabet_start
if one_based: cipher_number += 1
- plaintext_number = (
+ 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)
+ 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)
+ 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)
+ enciphered = [affine_decipher_letter(l, multiplier, adder, one_based)
for l in message]
return ''.join(enciphered)
-class Keyword_wrap_alphabet(Enum):
+class KeywordWrapAlphabet(Enum):
+ """Ways of wrapping the alphabet for keyword-based substitution ciphers."""
from_a = 1
from_last = 2
from_largest = 3
-def keyword_cipher_alphabet_of(keyword, wrap_alphabet=Keyword_wrap_alphabet.from_a):
+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', Keyword_wrap_alphabet.from_a)
+ >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_a)
'bayescdfghijklmnopqrtuvwxz'
- >>> keyword_cipher_alphabet_of('bayes', Keyword_wrap_alphabet.from_last)
+ >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_last)
'bayestuvwxzcdfghijklmnopqr'
- >>> keyword_cipher_alphabet_of('bayes', Keyword_wrap_alphabet.from_largest)
+ >>> keyword_cipher_alphabet_of('bayes', KeywordWrapAlphabet.from_largest)
'bayeszcdfghijklmnopqrtuvwx'
"""
- if wrap_alphabet == Keyword_wrap_alphabet.from_a:
- cipher_alphabet = ''.join(deduplicate(sanitise(keyword) +
+ if wrap_alphabet == KeywordWrapAlphabet.from_a:
+ cipher_alphabet = ''.join(deduplicate(sanitise(keyword) +
string.ascii_lowercase))
else:
- if wrap_alphabet == Keyword_wrap_alphabet.from_last:
+ 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:] +
+ deduplicate(sanitise(keyword) +
+ string.ascii_lowercase[last_keyword_position:] +
string.ascii_lowercase))
return cipher_alphabet
-def keyword_encipher(message, keyword, wrap_alphabet=Keyword_wrap_alphabet.from_a):
+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.
>>> keyword_encipher('test message', 'bayes')
'rsqr ksqqbds'
- >>> keyword_encipher('test message', 'bayes', Keyword_wrap_alphabet.from_a)
+ >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_a)
'rsqr ksqqbds'
- >>> keyword_encipher('test message', 'bayes', Keyword_wrap_alphabet.from_last)
+ >>> keyword_encipher('test message', 'bayes', KeywordWrapAlphabet.from_last)
'lskl dskkbus'
- >>> keyword_encipher('test message', 'bayes', Keyword_wrap_alphabet.from_largest)
+ >>> 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=Keyword_wrap_alphabet.from_a):
+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', Keyword_wrap_alphabet.from_a)
+ >>> keyword_decipher('rsqr ksqqbds', 'bayes', KeywordWrapAlphabet.from_a)
'test message'
- >>> keyword_decipher('lskl dskkbus', 'bayes', Keyword_wrap_alphabet.from_last)
+ >>> keyword_decipher('lskl dskkbus', 'bayes', KeywordWrapAlphabet.from_last)
'test message'
- >>> keyword_decipher('qspq jsppbcs', 'bayes', Keyword_wrap_alphabet.from_largest)
+ >>> keyword_decipher('qspq jsppbcs', 'bayes', KeywordWrapAlphabet.from_largest)
'test message'
"""
cipher_alphabet = keyword_cipher_alphabet_of(keyword, wrap_alphabet)
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
+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,
+ 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.
return transpositions
def pad(message_len, group_len, fillvalue):
+ """Returns the padding required to extend a message of message_len to an
+ even multiple of group_len, by adding repreated copies of fillvalue.
+ fillvalue can either be a character or a function that returns a character.
+
+ >>> pad(10, 4, '!')
+ '!!'
+ >>> pad(8, 4, '!')
+ ''
+ >>> pad(16, 4, '!')
+ ''
+ >>> pad(10, 4, lambda: '*')
+ '**'
+ """
padding_length = group_len - message_len % group_len
if padding_length == group_len: padding_length = 0
padding = ''
- for i in range(padding_length):
+ for _ 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):
+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.
else:
return ''.join(chain(*transposed))
-def column_transposition_decipher(message, keyword, fillvalue=' ',
- fillcolumnwise=False,
- emptycolumnwise=False):
+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.
>>> 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)
+ 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)
>>> 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,
+ return column_transposition_decipher(message, transpositions,
fillcolumnwise=True, emptycolumnwise=False)
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
+ 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'):
>>> pe.position
0
"""
- self.wheel1 = [('a', 'z'), ('b', 'e'), ('c', 'x'), ('d', 'k'),
- ('f', 'h'), ('g', 'j'), ('i', 'm'), ('l', 'r'), ('n', 'o'),
+ 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'),
+ 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)
else:
self.validate_wheel_spec(wheel)
self.make_wheel_map(wheel)
- self.position = ord(position) - ord('a')
+ 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
>>> pe.validate_wheel_spec([])
Traceback (most recent call last):
...
- ValueError: Wheel specification has 0 pairs, require 13
+ ValueError: Wheel specification has 0 pairs, requires 13
>>> pe.validate_wheel_spec([('a', 'b', 'c')]*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, require 13".
- format(len(wheel_spec)))
+ 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:
+ "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):
5
>>> ''.join([pe.lookup(l) for l in string.ascii_lowercase])
'udhbfejcpgmokrliwntsayqzvx'
+ >>> pe.lookup('A')
+ ''
"""
- return chr((self.wheel_map[(ord(letter) - ord('a') - self.position) % 26] + self.position) % 26 + ord('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.
self.position = (self.position + 1) % 26
return self.position
- def encipher(self, message):
+ def encipher(self, message, starting_position=None):
"""Enciphers a whole message.
>>> 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)
projects / cipher-training.git / blobdiff