Simple Python example of AES in ECB mode.

aes-ecb.py

from hashlib import md5
from base64 import b64decode
from base64 import b64encode
from Crypto.Cipher import AES


# Padding for the input string --not
# related to encryption itself.
BLOCK_SIZE = 16  # Bytes
pad = lambda s: s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * \
                chr(BLOCK_SIZE - len(s) % BLOCK_SIZE)
unpad = lambda s: s[:-ord(s[len(s) - 1:])]


class AESCipher:
    """
    Usage:
        c = AESCipher('password').encrypt('message')
        m = AESCipher('password').decrypt(c)
    Tested under Python 3 and PyCrypto 2.6.1.
    """

    def __init__(self, key):
        self.key = md5(key.encode('utf8')).hexdigest()

    def encrypt(self, raw):
        raw = pad(raw)
        cipher = AES.new(self.key.encode("utf8"), AES.MODE_ECB)
        return b64encode(cipher.encrypt(raw.encode('utf8')))

    def decrypt(self, enc):
        enc = b64decode(enc)
        cipher = AES.new(self.key.encode("utf8"), AES.MODE_ECB)
        return unpad(cipher.decrypt(enc)).decode('utf8')


##
# MAIN
# Just a test.
msg = input('Message...: ')
pwd = input('Password..: ')

print('Ciphertext:', AESCipher(pwd).encrypt(msg))

I tried to run this but i had this problem:

Message...: hello
Password..: 1234
Traceback (most recent call last):
File "aes-ecb.py", line 43, in
print('Ciphertext:', AESCipher(pwd).encrypt(msg))
File "aes-ecb.py", line 28, in encrypt
cipher = AES.new(self.key, AES.MODE_ECB)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/AES.py", line 232, in new
return _create_cipher(sys.modules[name], key, mode, *args, **kwargs)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/init.py", line 79, in _create_cipher
return modes[mode](factory, **kwargs)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/_mode_ecb.py", line 215, in _create_ecb_cipher
cipher_state = factory._create_base_cipher(kwargs)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/AES.py", line 103, in _create_base_cipher
result = start_operation(c_uint8_ptr(key),
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Util/_raw_api.py", line 238, in c_uint8_ptr
raise TypeError("Object type %s cannot be passed to C code" % type(data))
TypeError: Object type <class 'str'> cannot be passed to C code

@dimi

I tried to run this but i had this problem:

Message...: hello
Password..: 1234
Traceback (most recent call last):
File "aes-ecb.py", line 43, in
print('Ciphertext:', AESCipher(pwd).encrypt(msg))
File "aes-ecb.py", line 28, in encrypt
cipher = AES.new(self.key, AES.MODE_ECB)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/AES.py", line 232, in new
return _create_cipher(sys.modules[name], key, mode, *args, **kwargs)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/init.py", line 79, in _create_cipher
return modes[mode](factory, **kwargs)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/_mode_ecb.py", line 215, in _create_ecb_cipher
cipher_state = factory._create_base_cipher(kwargs)
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Cipher/AES.py", line 103, in _create_base_cipher
result = start_operation(c_uint8_ptr(key),
File "/home/papei1/.local/lib/python3.8/site-packages/Crypto/Util/_raw_api.py", line 238, in c_uint8_ptr
raise TypeError("Object type %s cannot be passed to C code" % type(data))
TypeError: Object type <class 'str'> cannot be passed to C code

fixed

ok now the output is:

Message...: hello
Password..: 1234
Ciphertext: b'NGTNQiu5fQEO7rfk9VxsNg=='

What about the decryption ?

i expected something like this for the decryption :
Ciphertext: NGTNQiu5fQEO7rfk9VxsNg==
Password..: 1234
Message...: hello