def test_xor_single_byte_decode(self):
source_str = binascii.hexlify(b'A').decode('ascii')
key = binascii.hexlify(b'B').decode('ascii')
crypt = crypt_utils.xor(source_str, key)
self.assertEqual(decryptor.single_byte_xor_decrypt(crypt, key), source_str)
source_str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
key = binascii.hexlify(b'h').decode('ascii')
crypt = ''.join(crypt_utils.xor(binascii.hexlify(bytes(c, 'ascii')).decode('ascii'), key) for c in source_str)
self.assertEqual(decryptor.single_byte_xor_decrypt(crypt, key), binascii.hexlify(bytes(source_str,'ascii')).decode('ascii').upper())
def encrypt_repeating_key_xor(data, key):
"""Implementation of repeating key xor. (ex 1.5)."""
message = ""
keygen = repeating_key_loop(key)
for b in crypt_utils.get_next_hex(data):
keybit = next(keygen)
enc = crypt_utils.xor(b, keybit)
if(len(enc) < 2): # ensure leading 0's are added to the byte if required
enc = '0' + enc
message += enc
return message
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 decrypt_repeating_key_xor(cyphertext, key):
"""Decrypts the cyphertext using the given key, using repeating xor cypher
Assumes the cyphertext is already hex"""
text = ""
keycode = encode.repeating_key_loop(key)
loc = 0
while loc < len(cyphertext):
b = cyphertext[loc:loc+2]
keybyte = next(keycode)
htext = crypt_utils.xor(b, keybyte)
if len(htext) < 2: # ensure leading '0' if only a single digit returned
htext = "0" + htext
text += htext
loc += 2
return binascii.unhexlify(text)
def test_xor(self):
self.assertEqual(crypt_utils.xor('F0','0F'),'FF')
self.assertEqual(crypt_utils.xor('1c0111001f010100061a024b53535009181c', '686974207468652062756c6c277320657965').lower(), '746865206b696420646f6e277420706c6179')
