bombe.py

   1 import string
   2 import collections
   3 import multiprocessing
   4 import itertools
   5 import logging
   6 from enigma import *
   7
   8
   9 logger = logging.getLogger('bombe')
  10 # logger.setLevel(logging.WARNING)
  11 # logger.setLevel(logging.INFO)
  12 logger.setLevel(logging.DEBUG)
  13
  14 # create the logging file handler
  15 fh = logging.FileHandler("enigma.log")
  16 formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
  17 fh.setFormatter(formatter)
  18
  19 # add handler to logger object
  20 logger.addHandler(fh)
  21
  22 ##################################
  23 # # Bombe
  24 ##################################
  25 #
  26 # Good explanation of [how the bombe worked](http://www.ellsbury.com/enigmabombe.htm) by Graham Ellsbury
  27 #
  28
  29 Signal = collections.namedtuple('Signal', ['bank', 'wire'])
  30 Connection = collections.namedtuple('Connection', ['banks', 'scrambler'])
  31 MenuItem = collections.namedtuple('MenuIem', ['before', 'after', 'number'])
  32
  33
  34 def make_menu(plaintext, ciphertext):
  35     return [MenuItem(p, c, i+1)
  36             for i, (p, c) in enumerate(zip(plaintext, ciphertext))]
  37
  38
  39 class Scrambler(object):
  40     def __init__(self, wheel1_spec, wheel2_spec, wheel3_spec, reflector_spec,
  41                  wheel1_pos='a', wheel2_pos='a', wheel3_pos='a'):
  42         self.wheel1 = SimpleWheel(wheel1_spec, position=wheel1_pos)
  43         self.wheel2 = SimpleWheel(wheel2_spec, position=wheel2_pos)
  44         self.wheel3 = SimpleWheel(wheel3_spec, position=wheel3_pos)
  45         self.reflector = Reflector(reflector_spec)
  46
  47     def __getattribute__(self, name):
  48         if name=='wheel_positions':
  49             return self.wheel1.position, self.wheel2.position, self.wheel3.position
  50         elif name=='wheel_positions_l':
  51             return self.wheel1.position_l, self.wheel2.position_l, self.wheel3.position_l
  52         else:
  53             return object.__getattribute__(self, name)
  54
  55     def advance(self, wheel1=False, wheel2=False, wheel3=True):
  56         if wheel1: self.wheel1.advance()
  57         if wheel2: self.wheel2.advance()
  58         if wheel3: self.wheel3.advance()
  59
  60     def lookup(self, letter):
  61         a = self.wheel3.forward(letter)
  62         b = self.wheel2.forward(a)
  63         c = self.wheel1.forward(b)
  64         d = self.reflector.forward(c)
  65         e = self.wheel1.backward(d)
  66         f = self.wheel2.backward(e)
  67         g = self.wheel3.backward(f)
  68         return g
  69
  70     def set_positions(self, wheel1_pos, wheel2_pos, wheel3_pos):
  71         self.wheel1.set_position(wheel1_pos)
  72         self.wheel2.set_position(wheel2_pos)
  73         self.wheel3.set_position(wheel3_pos)
  74
  75
  76 class Bombe(object):
  77
  78     def __init__(self, wheel1_spec, wheel2_spec, wheel3_spec, reflector_spec,
  79                 menu=None, start_signal=None, use_diagonal_board=True,
  80                 verify_plugboard=True):
  81         self.connections = []
  82         self.wheel1_spec = wheel1_spec
  83         self.wheel2_spec = wheel2_spec
  84         self.wheel3_spec = wheel3_spec
  85         self.reflector_spec = reflector_spec
  86         if menu:
  87             self.read_menu(menu)
  88         if start_signal:
  89             self.test_start = start_signal
  90         self.use_diagonal_board = use_diagonal_board
  91         self.verify_plugboard = verify_plugboard
  92
  93     def __getattribute__(self, name):
  94         if name=='wheel_positions':
  95             return self.connections[0].scrambler.wheel_positions
  96         elif name=='wheel_positions_l':
  97             return self.connections[0].scrambler.wheel_positions_l
  98         else:
  99             return object.__getattribute__(self, name)
 100
 101     def __call__(self, start_positions):
 102         return start_positions, self.test(initial_signal=self.test_start,
 103             start_positions=start_positions,
 104             use_diagonal_board=self.use_diagonal_board,
 105             verify_plugboard=self.verify_plugboard)
 106
 107     def add_connection(self, bank_before, bank_after, scrambler):
 108         self.connections += [Connection([bank_before, bank_after], scrambler)]
 109
 110     def read_menu(self, menu):
 111         self.connections = []
 112         for item in menu:
 113             scrambler = Scrambler(self.wheel1_spec, self.wheel2_spec, self.wheel3_spec,
 114                                   self.reflector_spec,
 115                                   wheel3_pos=unpos(item.number - 1))
 116             self.add_connection(item.before, item.after, scrambler)
 117         most_common_letter = (collections.Counter(m.before for m in menu) +\
 118             collections.Counter(m.after for m in menu)).most_common(1)[0][0]
 119         self.test_start = Signal(most_common_letter, most_common_letter)
 120
 121     def set_positions(self, wheel1_pos, wheel2_pos, wheel3_pos):
 122         for i, c in enumerate(self.connections):
 123             c.scrambler.set_positions(wheel1_pos, wheel2_pos, unpos(pos(wheel3_pos) + i))
 124
 125     def test(self, initial_signal=None, start_positions=None, use_diagonal_board=True,
 126             verify_plugboard=True):
 127         self.banks = {label:
 128                       dict(zip(string.ascii_lowercase, [False]*len(string.ascii_lowercase)))
 129                       for label in string.ascii_lowercase}
 130         if start_positions:
 131             self.set_positions(*start_positions)
 132         if not initial_signal:
 133             initial_signal = self.test_start
 134         self.pending = [initial_signal]
 135         self.propagate(use_diagonal_board)
 136         live_wire_count = len([self.banks[self.test_start.bank][w]
 137                     for w in self.banks[self.test_start.bank]
 138                     if self.banks[self.test_start.bank][w]])
 139         if live_wire_count < 26:
 140             if verify_plugboard:
 141                 possibles = self.possible_plugboards()
 142                 return all(s0.isdisjoint(s1) for s0 in possibles for s1 in possibles if s0 != s1)
 143             else:
 144                 return True
 145         else:
 146             return False
 147
 148     def propagate(self, use_diagonal_board):
 149         while self.pending:
 150             current = self.pending[0]
 151             # print("processing", current)
 152             logger.debug("Propogater processing {}".format(current))
 153             self.pending = self.pending[1:]
 154             if not self.banks[current.bank][current.wire]:
 155                 self.banks[current.bank][current.wire] = True
 156                 if use_diagonal_board:
 157                     self.pending += [Signal(current.wire, current.bank)]
 158                 for c in self.connections:
 159                     if current.bank in c.banks:
 160                         other_bank = [b for b in c.banks if b != current.bank][0]
 161                         other_wire = c.scrambler.lookup(current.wire)
 162                         # print("  adding", other_bank, other_wire, "because", c.banks)
 163                         logger.debug("Propogator adding {0} {1} because {2}".format(other_bank, other_wire, c.banks))
 164                         self.pending += [Signal(other_bank, other_wire)]
 165
 166     def run(self, run_start=None, wheel1_pos='a', wheel2_pos='a', wheel3_pos='a', use_diagonal_board=True):
 167         if not run_start:
 168             run_start = self.test_start
 169         self.solutions = []
 170         self.set_positions(wheel1_pos, wheel2_pos, wheel3_pos)
 171         for run_index in range(26*26*26):
 172             if self.test(initial_signal=run_start, use_diagonal_board=use_diagonal_board):
 173                 self.solutions += [self.connections[0].scrambler.wheel_positions_l]
 174             advance3 = True
 175             advance2 = False
 176             advance1 = False
 177             if (run_index + 1) % 26 == 0: advance2 = True
 178             if (run_index + 1) % (26*26) == 0: advance1 = True
 179             for c in self.connections:
 180                 c.scrambler.advance(advance1, advance2, advance3)
 181         return self.solutions
 182
 183     def possible_plugboards(self):
 184         possibles = set()
 185         for b in self.banks:
 186             active = [w for w in self.banks[b] if self.banks[b][w]]
 187             inactive = [w for w in self.banks[b] if not self.banks[b][w]]
 188             if len(active) == 1:
 189                 possibles = possibles.union({frozenset((b, active[0]))})
 190             if len(inactive) == 1:
 191                 possibles = possibles.union({frozenset((b, inactive[0]))})
 192         return possibles
 193
 194
 195 def run_multi_bombe(wheel1_spec, wheel2_spec, wheel3_spec, reflector_spec, menu,
 196                     start_signal=None, use_diagonal_board=True,
 197                     verify_plugboard=True):
 198     allwheels = itertools.product(string.ascii_lowercase, repeat=3)
 199
 200     with multiprocessing.Pool() as pool:
 201         res = pool.map(Bombe(wheel1_spec, wheel2_spec, wheel3_spec,
 202             reflector_spec, menu=menu, start_signal=start_signal,
 203             use_diagonal_board=use_diagonal_board,
 204             verify_plugboard=verify_plugboard),
 205                   allwheels)
 206     return [r[0] for r in res if r[1]]