def test_open_existing_dictionary(temp_dir):
# Create not existing language.
with Dictionary.open("english", create=True, _database_path=temp_dir) as _:
pass
# Open newly created language
with Dictionary.open("english",
_database_path=temp_dir) as english_dictionary:
assert english_dictionary._already_created()
def test_create_language(temp_dir):
"""Test a new language creation at database."""
english_dictionary = Dictionary("english", database_path=temp_dir)
english_dictionary._open()
assert not english_dictionary._already_created()
english_dictionary._create_dictionary()
assert english_dictionary._already_created()
english_dictionary._close()
def _dictionary_word_key_generator(
_database_path: Optional[str] = None) -> Iterator[str]:
""" Iterate through every word in our dictionaries. """
available_languages = Dictionary.get_available_languages(_database_path)
for language in available_languages:
with Dictionary.open(language, False,
_database_path) as language_dictionary:
words = language_dictionary.get_all_words()
for word in words:
yield word
def test_populate_database_histogram_from_text_file(temp_dir):
text_file_pathname = "cifra/tests/resources/english_book.txt"
with Dictionary.open("english", create=True,
_database_path=temp_dir) as current_dictionary:
current_dictionary.populate(text_file_pathname)
with Dictionary.open("english", create=False,
_database_path=temp_dir) as current_dictionary:
assert current_dictionary.letter_histogram["e"] == 35127
assert current_dictionary.letter_histogram["t"] == 26406
assert current_dictionary.letter_histogram["a"] == 24684
assert current_dictionary.letter_histogram["o"] == 22983
def main(args=sys.argv[1:], _database_path=None) -> None:
arguments: Dict[str, str] = parse_arguments(args)
# DICTIONARY MANAGEMENT
if arguments["mode"] == "dictionary":
if arguments["action"] == "create":
initial_words_file = arguments.get("initial_words_file", None)
with Dictionary.open(arguments["dictionary_name"],
create=True,
_database_path=_database_path) as dictionary:
if initial_words_file is not None:
dictionary.populate(initial_words_file)
elif arguments["action"] == "delete":
Dictionary.remove_dictionary(arguments["dictionary_name"],
_database_path=_database_path)
elif arguments["action"] == "update":
with Dictionary.open(arguments["dictionary_name"],
create=False,
_database_path=_database_path) as dictionary:
dictionary.populate(arguments["words_file"])
elif arguments["action"] == "list":
dictionaries = Dictionary.get_available_languages(
_database_path=_database_path)
for dictionary in dictionaries:
print(dictionary)
# CIPHERING MANAGEMENT
elif arguments["mode"] == "cipher":
ciphered_content = _process_file_with_key(
arguments["file_to_cipher"],
Algorithm.from_string(arguments["algorithm"]), arguments["key"],
MessageOperation.from_string(arguments["mode"]),
arguments["charset"] if "charset" in arguments else None)
_output_result(ciphered_content, arguments)
# DECIPHERING MANAGEMENT
elif arguments["mode"] == "decipher":
deciphered_content = _process_file_with_key(
arguments["file_to_decipher"],
Algorithm.from_string(arguments["algorithm"]), arguments["key"],
MessageOperation.from_string(arguments["mode"]),
arguments["charset"] if "charset" in arguments else None)
_output_result(deciphered_content, arguments)
# ATTACK MANAGEMENT
elif arguments["mode"] == "attack":
recovered_content = _attack_file(
arguments["file_to_attack"],
Algorithm.from_string(arguments["algorithm"]),
arguments["charset"] if "charset" in arguments else None,
_database_path=_database_path)
_output_result(recovered_content, arguments)
def test_populate_words_from_text_files(temporary_text_file):
text_file = temporary_text_file[0].name
text_without_punctuation_marks = temporary_text_file[1]
current_language = temporary_text_file[2]
temp_dir = temporary_text_file[3]
expected_set = set(text_without_punctuation_marks.lower().split())
with Dictionary.open(current_language,
create=True,
_database_path=temp_dir) as current_dictionary:
current_dictionary.populate(text_file)
with Dictionary.open(current_language,
_database_path=temp_dir) as current_dictionary:
for word in expected_set:
assert current_dictionary.word_exists(word)
def test_delete_language(loaded_dictionary_temp_dir):
"""Test delete a language also removes its words."""
language_to_remove = "german"
Dictionary.remove_dictionary(language_to_remove,
_database_path=loaded_dictionary_temp_dir)
# Check all words from removed language have been removed too.
not_existing_dictionary = Dictionary(language_to_remove,
loaded_dictionary_temp_dir)
not_existing_dictionary._open()
assert all(not not_existing_dictionary.word_exists(word, _testing=True)
for word in MICRO_DICTIONARIES[language_to_remove])
not_existing_dictionary._close()
def test_get_all_words(loaded_dictionary_temp_dir):
expected_words = ["yes", "no", "dog", "cat", "snake"]
with Dictionary.open(
"english", False,
_database_path=loaded_dictionary_temp_dir) as dictionary:
returned_words = dictionary.get_all_words()
assert set(returned_words) == set(expected_words)
def loaded_dictionary_temp_dir(tmp_path):
"""Create a dictionary at a temp dir filled with only a handful of words.
:return: Yields created temp_dir to host temporal dictionary database.
"""
# Load test data.
for language, words in MICRO_DICTIONARIES.items():
with Dictionary.open(language, create=True,
_database_path=tmp_path) as language_dictionary:
_ = [language_dictionary.add_word(word) for word in words]
# Check all words are stored at database:
for language, words in MICRO_DICTIONARIES.items():
with Dictionary.open(language,
_database_path=tmp_path) as language_dictionary:
assert all(language_dictionary.word_exists(word) for word in words)
yield tmp_path
def test_add_multiple_words(temp_dir):
language = "english"
with Dictionary.open(language, create=True,
_database_path=temp_dir) as dictionary:
assert all(not dictionary.word_exists(word)
for word in MICRO_DICTIONARIES[language])
dictionary.add_multiple_words(MICRO_DICTIONARIES[language])
assert all(
dictionary.word_exists(word)
for word in MICRO_DICTIONARIES[language])
def test_cwd_word(temp_dir):
"""Test if we can check for word existence, write a new word and finally delete it."""
word = "test"
with Dictionary.open("english", create=True,
_database_path=temp_dir) as english_dictionary:
assert not english_dictionary.word_exists(word)
english_dictionary.add_word(word)
assert english_dictionary.word_exists(word)
english_dictionary.remove_word(word)
assert not english_dictionary.word_exists(word)
def test_store_word_pattern(temp_dir):
"""Test word pattern is properly stored at database."""
word = "classification"
with Dictionary.open("test", create=True,
_database_path=temp_dir) as test_dictionary:
assert not test_dictionary.word_exists(word)
test_dictionary.add_word(word)
assert test_dictionary.word_exists(word)
words = test_dictionary.get_words_with_pattern(
"0.1.2.3.3.4.5.4.0.2.6.4.7.8")
assert word in words
def frequency_key_generator(
ciphered_text: str,
maximum_key_length: int = 5,
_database_path: Optional[str] = None) -> Iterator[str]:
""" Assess statistically given ciphertext to return most likely keys.
:param ciphered_text: Text to be deciphered.
:param maximum_key_length: Give keys up to given maximum key length.
:param _database_path: Absolute pathname to database file. Usually you don't
set this parameter, but it is useful for tests.
:return: An iterator through most likely keys below given length.
"""
likely_key_lengths = _get_likely_key_lengths(ciphered_text,
maximum_key_length)
keys_to_try: List[str] = []
for language in Dictionary.get_available_languages(_database_path):
with Dictionary.open(language, False,
_database_path) as language_dictionary:
for key_length in likely_key_lengths:
substrings = get_substrings(ciphered_text, key_length)
likely_keys = _get_likely_keys(substrings, language_dictionary)
keys_to_try.extend(likely_keys)
for key in keys_to_try:
yield key
def _get_word_mapping(charset: str, ciphered_word: str, dictionary: Dictionary) -> Mapping:
""" Create a mapping with characters candidates for given ciphered word.
:param charset: Charset used for substitution method. Both ends, ciphering
and deciphering, should use the same charset or original text won't be properly
recovered.
:param ciphered_word: Ciphered word used to find words with similar patterns.
:param dictionary: Dictionary to extract from words with the same pattern than ciphered word.
:return: A Mapping class instance.
"""
word_mapping = Mapping(charset)
ciphered_word_pattern = get_word_pattern(ciphered_word)
word_candidates = dictionary.get_words_with_pattern(ciphered_word_pattern)
for index, char in enumerate(ciphered_word):
for word_candidate in word_candidates:
word_mapping[char].add(word_candidate[index])
return word_mapping
def hack_substitution_mp(ciphered_text: str, charset: str = DEFAULT_CHARSET,
_database_path: Optional[str] = None) -> (str, float):
""" Get substitution ciphered text key.
Uses a word pattern matching technique to identify used language.
**You should use this function instead of *hack_substitution*.**
Whereas *hack_substitution* uses a sequential approach, this function uses
multiprocessing to improve performance.
:param ciphered_text: Text to be deciphered.
:param charset: Charset used for substitution method. Both ends, ciphering
and deciphering, should use the same charset or original text won't be properly
recovered.
:param _database_path: Absolute pathname to database file. Usually you don't
set this parameter, but it is useful for tests.
:return: A tuple with substitution key found and success probability.
"""
ciphered_words = get_words_from_text(ciphered_text)
available_languages = Dictionary.get_available_languages(_database_path=_database_path)
keys_found: Dict[str, float] = dict() # Keys are charset keys and values valid probabilities.
with multiprocessing.Pool(_get_usable_cpus()) as pool:
nargs = ((language, ciphered_words, charset, _database_path) for language in available_languages)
possible_mappings: List[Tuple[List[Mapping], str]] = pool.starmap(_get_possible_mappings, nargs)
# I could have passed the entire mappings list to _assess_candidates_keys() but
# in my tests I've discovered to be more perfomant to extract every element from
# mappings list and passing them as one element lists.
nargs = ((ciphered_text, language, [mapping], charset, _database_path)
for mappings, language in possible_mappings for mapping in mappings)
language_keys_list: List[Dict[str, float]] = pool.starmap(_assess_candidate_keys, nargs)
for language_keys in language_keys_list:
# It would be extremely odd, but two languages may generate the same key.
# So we must keep the one with higher probability.
for key in keys_found:
if key in language_keys:
if language_keys[key] < keys_found[key]:
language_keys.pop(key)
# Now, languages_keys should have keys not yet present at keys_found or
# with smaller probability.
keys_found.update(language_keys)
best_key, best_probability = _get_best_key(keys_found)
return best_key, best_probability
def _generate_language_mapping(language: str, ciphered_words: Set[str],
charset: str = DEFAULT_CHARSET,
_database_path: Optional[str] = None) -> Mapping:
""" Generate a mapping with all letter candidates in given language for every
cipherletter.
:param language: Language to look letter candidates into.
:param ciphered_words: Every cipherword in message.
:param charset: Charset used for substitution. Both ends, ciphering
and deciphering, should use the same charset or original text won't be properly
recovered.
:param _database_path: Absolute pathname to database file. Usually you don't
set this parameter, but it is useful for tests.
:return: Mapping loaded with all candidates in given language.
"""
language_mapping = Mapping(charset)
with Dictionary.open(language, False, _database_path=_database_path) as dictionary:
for ciphered_word in ciphered_words:
word_mapping = _get_word_mapping(charset, ciphered_word, dictionary)
language_mapping.reduce_mapping(word_mapping)
return language_mapping
def loaded_dictionaries() -> LoadedDictionaries:
"""Create a dictionaries database at a temp dir filled with four languages.
Languages in database are: english, spanish, french and german.
:return: Yields a LoadedDictionary fill info of temporal dictionaries database.
"""
with tempfile.TemporaryDirectory() as temp_dir:
resources_path = os.path.join(temp_dir, "resources")
os.mkdir(resources_path)
copy_files([
f"cifra/tests/resources/{language}_book.txt"
for language in LANGUAGES
], resources_path)
for language in LANGUAGES:
with Dictionary.open(language=language,
create=True,
_database_path=temp_dir) as dictionary:
language_book = os.path.join(temp_dir,
f"resources/{language}_book.txt")
dictionary.populate(language_book)
yield LoadedDictionaries(temp_dir=temp_dir, languages=LANGUAGES)
def hack_substitution(ciphered_text: str, charset: str = DEFAULT_CHARSET,
_database_path: Optional[str] = None) -> (str, float):
""" Get substitution ciphered text key.
Uses a word pattern matching technique to identify used language.
**You should not use this function. Use *hack_substitution_mp* instead.** This
function is slower than *mp* one because is sequential while the other uses a
multiprocessing approach. This function only stay here to allow comparisons
between sequential and multiprocessing approaches.
:param ciphered_text: Text to be deciphered.
:param charset: Charset used for substitution method. Both ends, ciphering
and deciphering, should use the same charset or original text won't be properly
recovered.
:param _database_path: Absolute pathname to database file. Usually you don't
set this parameter, but it is useful for tests.
:return: A tuple with substitution key found and success probability.
"""
ciphered_words = get_words_from_text(ciphered_text)
available_languages = Dictionary.get_available_languages(_database_path=_database_path)
keys_found: Dict[str, float] = dict() # Keys are charset keys and values valid probabilities.
for language in available_languages:
possible_mappings, _ = _get_possible_mappings(language, ciphered_words, charset, _database_path)
language_keys = _assess_candidate_keys(ciphered_text, language, possible_mappings, charset, _database_path)
# It would be extremely odd, but two languages may generate the same key.
# So we must keep the one with higher probability.
for key in keys_found:
if key in language_keys:
if language_keys[key] < keys_found[key]:
language_keys.pop(key)
# Now, languages_keys should have keys not yet present at keys_found or
# with smaller probability.
keys_found.update(language_keys)
best_key, best_probability = _get_best_key(keys_found)
return best_key, best_probability
def test_get_dictionaries_names(loaded_dictionaries: LoadedDictionaries):
dictionaries_names = Dictionary.get_available_languages(
_database_path=loaded_dictionaries.temp_dir)
assert dictionaries_names == loaded_dictionaries.languages
def test_open_not_existing_dictionary(temp_dir):
with pytest.raises(NotExistingLanguage):
with Dictionary.open("english", _database_path=temp_dir) as _:
pass
