def test_caesar_custom_charsets(self, msg):
# Test custom charsets
charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
plaintext = msg["plaintext"]
ciphertext = "M EGBqD EqoDqF yqEEmsq"
# Test encrypt
c = caesar(plaintext, msg["key"], "encrypt", charset=charset)
assert c == ciphertext
# Test decrypt
c = caesar(ciphertext, msg["key"], "decrypt", charset=charset)
assert c == plaintext
def run(self, text):
""" Run the automatic key finding """
# strip all non letter characters
letters_only = letters_only_uppercase(text)
# all the possible lengths to test
lengths = list(range(2, min(50, len(letters_only))))
# set the number of possibilities
self.set_total_possibilities(len(lengths))
# pre-calculate the entire text decrypted with all the caesar shifts
reverse_caesars = {}
for shift, letter in enumerate(ascii_uppercase):
reverse_caesars[letter] = caesar(letters_only, -shift)
# store the found keys
found_keys = set()
# iterate over each length to check
for length in lengths:
# try and find the best key that is `length` long
key = best_n_long_key(letters_only, reverse_caesars, length)
shifts = string_to_shifts(key)
# check if key is double an existing key
if len(key) % 2 == 0:
first_half = key[:len(key) // 2]
second_half = key[len(key) // 2:]
if first_half == second_half and first_half in found_keys:
# this new key is double an existing key, the solver is done
self.done()
return
found_keys.add(key)
self.possibility(key, reverse_vigenere(text, shifts))
self.done()
def test_caesar_exceptions_non_integer_key(self, msg):
# Test non-integer key raises exception
with pytest.raises(ValueError):
caesar(msg["plaintext"], "foo", "encrypt")
def test_caesar_exceptions_bad_action(self, msg):
# Test bad action
with pytest.raises(ValueError):
# Action must be either encrypt or decrypt
caesar(msg["plaintext"], msg["key"], "foobar")
def test_caesar_exceptions_duplicates_in_charset(self, msg):
# Test bad charset
with pytest.raises(ValueError):
# this contains duplicates so should raise a ValueError
charset = "asdfghjklkkjhedbb"
caesar(msg["plaintext"], msg["key"], "encrypt", charset=charset)
def test_caesar_decryption(self, msg):
# Test decryption
c = caesar(msg["caesar_ciphertext"], msg["key"], "decrypt")
assert c == msg["plaintext"]
def test_caesar_reverse(self):
self.assertEqual(caesar("Spwwz Hzcwo", -11), "Hello World")
self.assertEqual(
caesar("Trvjri Tzgyvi zj r dfefrcgyrsvkzt jlsjkzklkzfe tzgyvi",
-17),
"Caesar Cipher is a monoalphabetic substitution cipher")