def get_widget(self):
""" Get the widget for this cipher.
Returns:
A Gtk.Widget used to control this plugin.
"""
if self._plugin_controller is None:
self._plugin_controller = PluginController(self._parent, self)
return self._plugin_controller.get_widget()
class ColumnTranspositionCipher(Cipher):
"""
An implementation of column transposition cipher.
"""
_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
def __init__(self, parent):
""" Create a new ColumnTranspositionCipher instance.
Args:
parent: a class that provides an interface to CryptographyStudio
"""
self._parent = parent
self._plugin_controller = None
self.set_fill_char("X")
def encrypt(self, plaintext, key):
""" Encrypt the given text.
Args:
plaintext: string, text to encrypt
key: list, key used for encryption
Returns:
String containing encrypted text.
"""
square = self.make_square(plaintext, len(key))
return ''.join(self.transpose(square, self.inverse(key)))
def decrypt(self, ciphertext, key):
""" Decrypt the given text.
Args:
ciphertext: string, text to decrypt
key: list, key used for decryption
Returns:
String containing decrypted text.
"""
ln = int(len(ciphertext) / len(key))
square = [ciphertext[i:i+ln] for i in range(0, len(ciphertext), ln)]
return self.read_square(self.transpose(square, key))
def get_widget(self):
""" Get the widget for this cipher.
Returns:
A Gtk.Widget used to control this plugin.
"""
if self._plugin_controller is None:
self._plugin_controller = PluginController(self._parent, self)
return self._plugin_controller.get_widget()
def set_fill_char(self, char):
self._fill_char = char[0]
def make_square(self, text, dim):
sqr = [''] * dim
i = 0
j = 0
while i < len(text) or j % dim != 0:
if i >= len(text) or text[i].upper() in self._CHARS:
sqr[j % dim] += text[i] if i < len(text) else self._fill_char
j += 1
i += 1
return sqr
@classmethod
def read_square(cls, square):
return ''.join(''.join(s) for s in zip(*square))
@classmethod
def transpose(cls, square, key):
return [square[i] for i in key]
@classmethod
def inverse(cls, key):
inv_key = [0] * len(key)
for i, k in enumerate(key):
inv_key[k] = i
return inv_key
