def EncryptAES(message, key):
if len(key) != 16:
raise ValueError(
"Key must be 16 bytes (for AES-128, I didn't implement others)")
# get round keys
round_keys = MakeRoundKeys(exp_key=KeyExpansion(key, Nk=4), rounds=11)
# pad message and convert to byte blocks
message = pad(message, 16)
msg_blocks = [message[i:i + 16] for i in range(0, len(message), 16)]
cipher_blocks = [None] * len(msg_blocks)
for m in range(len(cipher_blocks)):
state = msg_blocks[m]
# round 0
state = AddRoundKey(state, round_keys[0])
# rounds 1-10
for r in range(1, 11):
state = SubBytes(state)
state = ShiftRows(state)
# mix columns omitted for last round
if (r != 10):
state = MixColumns(state)
state = AddRoundKey(state, round_keys[r])
cipher_blocks[m] = state
return b''.join(cipher_blocks)
def encrypt(self, plaintext):
# handle bytes or string input
if isinstance(plaintext, str):
plaintext = plaintext.encode('ascii')
elif isinstance(plaintext, bytes):
None
else:
raise Exception("plaintext input is not str or bytes object")
# break plaintext into chunks
plaintext = pad(plaintext, 16)
msg_blocks = [
plaintext[i:i + 16] for i in range(0, len(plaintext), 16)
]
# initialize encrypted blocks
cipher_blocks = [None] * len(msg_blocks)
for m in range(0, len(msg_blocks)):
# xor prev ciphertext block
if m == 0:
xor_block = xor(msg_blocks[m], self._iv)
else:
xor_block = xor(msg_blocks[m], cipher_blocks[m - 1])
# use block cipher
cipher_blocks[m] = self._aes_cipher.encrypt(xor_block)
return b''.join(cipher_blocks)
def encrypt(self, insert):
return self._aes_cipher.encrypt(pad(self.make_text(insert), 16))
def make_text(self, insert):
return pad(
self._prefix + insert.encode('ascii') +
b64decode(self._b64_target), 16)
def encrypt(self, plaintext):
"""encrypt using that key"""
return self._aes_cipher.encrypt(pad(plaintext.encode('ascii'), 16))