def test_decrypt(self):
"""Tests decrypt function for Caesar cipher"""
self.assertEqual(
Vigenere.decrypt(ALPHABET, ALPHABET), 'A' * 26)
self.assertEqual(
Vigenere.decrypt(ALPHABET[:13] * 2, ALPHABET[:13]), 'A' * 26)
self.assertEqual(
Vigenere.decrypt(ALPHABET[::2] * 2, ALPHABET), ALPHABET)
with self.assertRaises(Vigenere.VigenereError):
Vigenere.decrypt(5, ALPHABET)
with self.assertRaises(Vigenere.VigenereError):
Vigenere.decrypt(ALPHABET, range(5))
def decrypt(text, key):
"""Decrypts text using the One-Time Pad cipher
D(x) = Vigenere.decrypt(text, key)
text : string
key : string
"""
if type(text) is not str:
raise OneTimePadError('Can only encrypt strings.')
if type(key) is not str:
raise OneTimePadError('key must be a string.')
if len(key) < len(text):
raise OneTimePadError('key must be at least the same length as text.')
return Vigenere.decrypt(utils.fix_text(text), utils.fix_text(key))
def __decrypt(message, key):
# Split message in half
B = message[:len(message) / 2]
C = message[len(message) / 2:]
Rail_Fence_key = Jordan_Harman_Algorithm_1.get_rail_key(key)
Caesar_key = Jordan_Harman_Algorithm_1.get_caesar_key(key)
Vigenere_key = Jordan_Harman_Algorithm_1.get_vigenere_key(key)
# Begin Rounds
for x in range(0, 8):
C = Caesar.decrypt(C, Caesar_key)
C = Rail_Fence.decrypt(C, Rail_Fence_key)
C = Vigenere.decrypt(C, Vigenere_key)
B, C = C, B
return B + C
def choose_cipher(cipher_name, key, option, input_file, output_file):
#Playfair
if cipher_name == "PLF":
if option == "ENC":
pass
elif option == "DEC":
pass
else:
print("Invalid option! Options are ENC/DEC")
#Row Transposition
elif cipher_name == "RTS":
rowtransposition = RowTransposition()
rowtransposition.setKey(key)
if option == "ENC":
plain_text = read_file(input_file)
cipher_text = rowtransposition.encrypt(plain_text)
write_file(output_file, cipher_text)
elif option == "DEC":
cipher_text = read_file(input_file)
plain_text = rowtransposition.decrypt(cipher_text)
write_file(output_file, plain_text)
else:
print("Invalid option! Options are ENC/DEC")
#Railfence
elif cipher_name == "RFC":
railfence = Railfence()
railfence.setKey(key)
if option == "ENC":
plain_text = read_file(input_file)
cipher_text = railfence.encrypt(plain_text)
write_file(output_file, cipher_text)
elif option == "DEC":
cipher_text = read_file(input_file)
plain_text = railfence.decrypt(cipher_text)
write_file(output_file, plain_text)
else:
print("Invalid option! Options are ENC/DEC")
#Vigenere
elif cipher_name == "VIG":
vigenere = Vigenere()
vigenere.setKey(key)
if option == "ENC":
plain_text = read_file(input_file)
cipher_text = vigenere.encrypt(plain_text)
write_file(output_file, cipher_text)
elif option == "DEC":
cipher_text = read_file(input_file)
plain_text = vigenere.decrypt(cipher_text)
write_file(output_file, plain_text)
else:
print("Invalid option! Options are ENC/DEC")
#Caesar
elif cipher_name == "CES":
caesar = Caesar()
caesar.setKey(int(key))
if option == "ENC":
plain_text = read_file(input_file)
cipher_text = caesar.encrypt(plain_text)
write_file(output_file, cipher_text)
elif option == "DEC":
cipher_text = read_file(input_file)
plain_text = caesar.decrypt(cipher_text)
write_file(output_file, plain_text)
else:
print("Invalid option! Options are ENC/DEC")
else:
print("Invalid cipher name chosen!")
