y2yB0gQ9

1import base64
2import hashlib
3
4from Crypto.Cipher import AES
5
6class MulaEncryption:
7    # The block size to be used while padding
8    BS = 16
9
10    def __init__(self, secret_key, iv_key):
11        """Initialises the Class with the parameters passed.
12
13        :param secret_key:
14        The secret key to use in the symmetric cipher.
15        It must be 16 bytes long
16        :type secret_key: string
17
18        :param iv_key:
19        The initialization vector key to use in the symmetric cipher.
20        It must be 16 bytes long
21        :type iv_key: string
22        """
23
24        # Hash the secret key
25        self.secret_key_hash = hashlib.sha256(secret_key.encode()).hexdigest()[:32]
26
27        # Hash the IV Key
28        self.iv_hash = hashlib.sha256(iv_key.encode()).hexdigest()[:16]
29
30    def pad(self, string):
31        """Introduces extra bytes for strings less than the block size
32
33        :param string:
34        The string value of the text to be padded
35        :type string: string
36
37        :return: string
38        """
39        return string + (self.BS - len(string) % self.BS) * chr(self.BS - len(string) % self.BS)
40
41    def encrypt(self, params):
42        """Encrypts the params passed with the IV and secret key passed while initializing this class
43
44        :param params:
45        The string value of the text to be encrypted
46        :type params: string
47
48        :return: string: Encrypted string
49        """
50        cipher = AES.new(self.secret_key_hash.encode(), AES.MODE_CBC, self.iv_hash.encode())
51
52        string = cipher.encrypt(self.pad(params).encode())
53        return base64.b64encode(base64.b64encode(string))