aes-python.py

from Crypto.Cipher import AES
from Crypto.Hash import MD5
from Crypto import Random
import base64

# pip install pycrypto

class AESCrypto:
    
    def md5_hash(self,text):
        h = MD5.new()
        h.update(text)
        return h.hexdigest()
    
    def __init__(self,key):
        # 128 bits
        self.key = self.md5_hash(key)


    def encrypt(self,cleartext):
        Block_Size = AES.block_size         # Block size - 128 bits
        pad = lambda s: s + (Block_Size - len (s) % Block_Size) * chr (Block_Size - len (s) % Block_Size)
        cleartext_blocks = pad(cleartext)
        
        iv = Random.new().read(Block_Size) # Random IV 
        crypto = AES.new(self.key,AES.MODE_CBC,iv)
        return base64.b64encode(iv + crypto.encrypt(cleartext_blocks))   
    
    def decrypt(self,enctext):
        enctext = base64.b64decode(enctext)
        iv = enctext[:16]
        crypto = AES.new(self.key,AES.MODE_CBC,iv)
        unpad = lambda s : s[0:-ord(s[-1])] # Unpad
        return unpad(crypto.decrypt(enctext[16:]))     

aes = AESCrypto('p@ssw0rd')
encrypted = aes.encrypt('Hello World')
print encrypted
decrypted = aes.decrypt(encrypted)
print decrypted