def single_byte_xor_decrypt(message, key):
'''Key should be a single character, represented in Hex.'''
if not crypt_utils.is_hex(message) or not crypt_utils.is_hex(key):
raise TypeError("Error: message and key expected in Hex format")
decode = ''
for i in range(len(message), 0, -2):
b = message[i-2:i]
tmp = crypt_utils.xor(b, key)
if len(tmp) < 2:
tmp = '0' + tmp
decode = tmp + decode
return decode
def hex_to_base64(hex_string):
if type(hex_string) != str and type(hex_string) != bytes:
raise TypeError("Error: hex_to_base64 requires a string")
if not crypt_utils.is_hex(hex_string):
raise TypeError("Error: passed data is not Hex")
if type(hex_string) is not bytes:
hex_string = bytes(hex_string, 'UTF8')
s = binascii.unhexlify(hex_string)
return str(base64.standard_b64encode(s))[2:-1]
def crack_vigenere(cyphertext):
if not crypt_utils.is_hex(cyphertext):
cyphertext = crypt_utils.toHex(cyphertext)
keysizes = generate_vigenere_key_sizes(cyphertext)
options = {}
for keysize in keysizes:
blocks = vigenere_blocks(cyphertext, keysize)
try:
# Chunk the hex strings into 8 bit lengths (2 Hex digits)
# Otherwise transpose would split bytes incorrectly
blocks = [[s[i] + s[i+1] for i in range(0, len(s), 2)] for s in blocks]
except IndexError:
# blocks contain invalid Hex, so assume this is not the solution
continue
blocks = vigenere_transpose(blocks)
decrypted_message = []
key = ''
for block in blocks:
key_byte, message_part = search_single_byte_xor_key(block)
decrypted_message.append(message_part)
key += key_byte
decrypted_message = vigenere_transpose(decrypted_message)
decrypted_message = ''.join(decrypted_message)
score = score_char_freq(decrypted_message)
try:
key = binascii.unhexlify(key).decode('ascii')
except:
#if key cannot be converted to ascii, leave as is
pass
options[score] = (key, decrypted_message)
return options[min(options)]
def test_is_hex(self):
self.assertTrue(crypt_utils.is_hex('0'))
self.assertTrue(crypt_utils.is_hex('1'))
self.assertTrue(crypt_utils.is_hex('2'))
self.assertTrue(crypt_utils.is_hex('3'))
self.assertTrue(crypt_utils.is_hex('4'))
self.assertTrue(crypt_utils.is_hex('5'))
self.assertTrue(crypt_utils.is_hex('6'))
self.assertTrue(crypt_utils.is_hex('7'))
self.assertTrue(crypt_utils.is_hex('8'))
self.assertTrue(crypt_utils.is_hex('9'))
self.assertTrue(crypt_utils.is_hex('A'))
self.assertTrue(crypt_utils.is_hex('B'))
self.assertTrue(crypt_utils.is_hex('C'))
self.assertTrue(crypt_utils.is_hex('D'))
self.assertTrue(crypt_utils.is_hex('E'))
self.assertTrue(crypt_utils.is_hex('F'))
self.assertTrue(crypt_utils.is_hex('AF'))
self.assertTrue(crypt_utils.is_hex('23'))
self.assertTrue(crypt_utils.is_hex('1A0F5'))
self.assertTrue(crypt_utils.is_hex('A0F5DF'))
self.assertTrue(crypt_utils.is_hex('A0F5D34FAB45Bc54Abcd12345002300Fd'))
self.assertFalse(crypt_utils.is_hex('G'))
self.assertFalse(crypt_utils.is_hex('Z'))
self.assertFalse(crypt_utils.is_hex('FA00M'))
self.assertFalse(crypt_utils.is_hex('&'))
self.assertFalse(crypt_utils.is_hex(''))
