def __init__(self, parent):
""" Create a new VigenereCipherAnalyzer instance.
Args:
parent: a class that provides an interafce to CryptographyStudio
"""
super().__init__(parent)
self._cipher = VigenereCipher(parent)
self._widget.show_all()
key_path = path.join(self.GLADE_LOCATION, "resources", self.KEY_GLADE)
with open(key_path, "r") as fp:
self._key_selector_buffer = fp.read()
ngram_loader = NGramLoader()
ngram_loader.load("hr.json")
self._letter_freqs = ngram_loader.get_ngrams(1)
self._update_key_length()
class VigenereCipherAnalyzer(WidgetController, CipherAnalyzer):
GLADE_LOCATION = path.dirname(__file__)
KEY_GLADE = "key_selector.glade"
TRY_BUTTON_ID = "try_button"
KEY_LENGTH_ENTRY_ID = "key_length_entry"
KEY_SELECTOR_ID = "key_selector"
KEY_SELECTOR_BOX_ID = "key_selector_box"
KEY_SELECTOR_CI_ID = "ci_field"
KEY_SELECTOR_MCI_ID = "mic_store"
KEY_SELECTOR_MCI_VIEW = "mic_view"
CINDEX_FIELD_ID = "coincidency_index_field"
LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
def __init__(self, parent):
""" Create a new VigenereCipherAnalyzer instance.
Args:
parent: a class that provides an interafce to CryptographyStudio
"""
super().__init__(parent)
self._cipher = VigenereCipher(parent)
self._widget.show_all()
key_path = path.join(self.GLADE_LOCATION, "resources", self.KEY_GLADE)
with open(key_path, "r") as fp:
self._key_selector_buffer = fp.read()
ngram_loader = NGramLoader()
ngram_loader.load("hr.json")
self._letter_freqs = ngram_loader.get_ngrams(1)
self._update_key_length()
def _build_gui(self):
""" Build the widget UI of this WidgetController. """
super()._build_gui()
def _load_gui_objects(self):
""" Save references to required objects defined in the .glade file. """
super()._load_gui_objects()
self._try_button = self._builder.get_object(self.TRY_BUTTON_ID)
self._key_length_entry = \
self._builder.get_object(self.KEY_LENGTH_ENTRY_ID)
self._key_selector = \
self._cindex_field = self._builder.get_object(self.CINDEX_FIELD_ID)
self._key_selector = self._builder.get_object(self.KEY_SELECTOR_ID)
def _connect_handlers(self):
""" Connect signals with their handler methods. """
super()._connect_handlers()
self._try_button.connect("clicked", self._try_key)
self._key_length_entry.connect("value-changed",
self._update_key_length)
def _update_key_length(self, *args):
ciphertext = self._parent.get_ciphertext()
m = int(self._key_length_entry.get_text())
self._key_length = m
self._create_key_selectors()
freq = [{} for _ in range(m)]
ttl = [0] * m
filtered = filter(lambda x: x in self.LETTERS, ciphertext.upper())
avg = 0
for i, c in enumerate("".join(filtered)):
ttl[i % m] += 1
if c in freq[i % m]:
freq[i % m][c] += 1
else:
freq[i % m][c] = 1
for i, cs in enumerate(self._cis):
ci = 0;
for value in freq[i].values():
ci += value * (value - 1)
if ttl[i] > 1:
ci /= ttl[i] * (ttl[i] - 1)
else:
ci = 0
avg += ci
cs.set_text(str(ci)[:5])
self._cindex_field.set_text(str(avg/m)[:5])
def _create_key_selectors(self):
count = self._key_length
for child in self._key_selector.get_children():
child.destroy()
selector_data = [self._create_key_selector()
for i in range(count)]
boxes, cis, mcis, self._mci_views = zip(*selector_data)
self._cis, self._mcis = cis, mcis
for box in boxes:
self._key_selector.pack_start(box, False, False, 5)
for i in range(len(mcis)):
self._update_mci(i)
def _update_mci(self, mci_id):
ciphertext = self._parent.get_ciphertext()
filtered = "".join(x for x in ciphertext.upper() if x in self.LETTERS)
def mv(char, inc):
return chr((ord(char) - ord('A') + inc) % 26 + ord('A'))
for ind in range(len(self.LETTERS)):
freq = {}
ttl = 0
for i in range(mci_id, len(filtered), self._key_length):
fi = filtered[i]
if fi in freq:
freq[fi] += 1
else:
freq[fi] = 1
ttl += 1
mci = 0
for l, f in self._letter_freqs.items():
mci += f * freq.get(mv(l, ind), 0)
if ttl > 0:
mci /= ttl
else:
mci = 0
self._mcis[mci_id].append([
chr(ord('A') + ind),
mci,
int(mci * 1000)])
self._mcis[mci_id].set_sort_column_id(1, Gtk.SortType.DESCENDING)
def _create_key_selector(self):
builder = Gtk.Builder.new_from_string(self._key_selector_buffer, -1)
return (
builder.get_object(self.KEY_SELECTOR_BOX_ID),
builder.get_object(self.KEY_SELECTOR_CI_ID),
builder.get_object(self.KEY_SELECTOR_MCI_ID),
builder.get_object(self.KEY_SELECTOR_MCI_VIEW)
)
def _get_key(self):
key = ''
for mci, mci_view in zip(self._mcis, self._mci_views):
path, column = mci_view.get_cursor()
if not path:
path = Gtk.TreePath.new_first()
mci_view.set_cursor(path)
key += mci.get(mci.get_iter(path), 0)[0]
return key
def _try_key(self, *args):
""" A handler method that trys to decrypt the text in the parents
ciphertext view.
Args:
*args: arguments passed from the signal
"""
key = self._get_key()
ciphertext = self._parent.get_ciphertext()
self._parent.set_plaintext(self._cipher.decrypt(ciphertext, key))
