bombe.py

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