[docs] Python encryption example

Author: capcom6

web/mkdocs/docs/privacy/encryption.md

@@ -175,4 +175,69 @@ class Encryptor {
         return crypto.pbkdf2Sync(passphrase, salt, iterations, keyLength, "sha1");
     }
 }
+```
+
+### Python
+
+Based on [pycryptodome](https://pypi.org/project/pycryptodome/)
+
+```python
+from Crypto.Cipher import AES
+from Crypto.Hash import SHA1
+from Crypto.Protocol.KDF import PBKDF2
+from Crypto.Random import get_random_bytes
+from Crypto.Util.Padding import pad, unpad
+
+class AESEncryptor(BaseEncryptor):
+    def encrypt(self, cleartext: str) -> str:
+        saltBytes = self._generate_salt()
+        key = self._generate_key(saltBytes, self.iterations)
+
+        cipher = AES.new(key, AES.MODE_CBC, iv=saltBytes)
+
+        encrypted_bytes = cipher.encrypt(pad(cleartext.encode(), AES.block_size))
+
+        salt = base64.b64encode(saltBytes).decode("utf-8")
+        encrypted = base64.b64encode(encrypted_bytes).decode("utf-8")
+
+        return f"$aes-256-cbc/pbkdf2-sha1$i={self.iterations}${salt}${encrypted}"
+
+    def decrypt(self, encrypted: str) -> str:
+        chunks = encrypted.split("$")
+
+        if len(chunks) < 5:
+            raise ValueError("Invalid encryption format")
+
+        if chunks[1] != "aes-256-cbc/pbkdf2-sha1":
+            raise ValueError("Unsupported algorithm")
+
+        params = self._parse_params(chunks[2])
+        if "i" not in params:
+            raise ValueError("Missing iteration count")
+
+        iterations = int(params["i"])
+        salt = base64.b64decode(chunks[-2])
+        encrypted_bytes = base64.b64decode(chunks[-1])
+
+        key = self._generate_key(salt, iterations)
+        cipher = AES.new(key, AES.MODE_CBC, iv=salt)
+
+        decrypted_bytes = unpad(cipher.decrypt(encrypted_bytes), AES.block_size)
+
+        return decrypted_bytes.decode("utf-8")
+
+    def _generate_salt(self) -> bytes:
+        return get_random_bytes(16)
+
+    def _generate_key(self, salt: bytes, iterations: int) -> bytes:
+        return PBKDF2(
+            self.passphrase,
+            salt,
+            count=iterations,
+            dkLen=32,
+            hmac_hash_module=SHA1,
+        )
+
+    def _parse_params(self, params: str) -> t.Dict[str, str]:
+        return {k: v for k, v in [p.split("=") for p in params.split(",")]}
 ```