AESexample.py

from Crypto import Random
from Crypto.Cipher import AES
import base64
import hashlib

class AESCipher(object):

    def __init__(self, key): 
        self.bs = 32
        self.key = hashlib.sha256(key.encode()).digest()

    def encrypt(self, raw):
        raw = self._pad(raw)
        iv = Random.new().read(AES.block_size)
        cipher = AES.new(self.key, AES.MODE_ECB, iv)
        return base64.b64encode(iv + cipher.encrypt(raw))

    def decrypt(self, enc):
        enc = base64.b64decode(enc)
        iv = enc[:AES.block_size]
        cipher = AES.new(self.key, AES.MODE_ECB, iv)
        return self._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8')

    def _pad(self, s):
        return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)

    @staticmethod
    def _unpad(s):
        return s[:-ord(s[len(s)-1:])]
        
def main():
	secretKey = file("secretkey","rb").read(32)
	obj = AESCipher(secretKey)
	plain = file("sample.bmp","rb").read()
	enc = obj.encrypt(plain)
	enc = base64.b64decode(enc)
	iv = enc[:AES.block_size]

	temp = file("./results/AESECB.bmp","wb")
	temp.write(enc[AES.block_size:])
	temp.close()

if __name__ == "__main__":
	main()