diff --git a/setup.py b/setup.py
index dca0c13..f20dc4d 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 
 setuptools.setup(
     name="tesla_fleet_api",
-    version="0.8.1",
+    version="0.8.2",
     author="Brett Adams",
     author_email="hello@teslemetry.com",
     description="Tesla Fleet API library for Python",
diff --git a/tesla_fleet_api/const.py b/tesla_fleet_api/const.py
index 957d8b7..b7b652b 100644
--- a/tesla_fleet_api/const.py
+++ b/tesla_fleet_api/const.py
@@ -3,7 +3,7 @@
 from enum import Enum
 import logging
 
-VERSION = "0.8.1"
+VERSION = "0.8.2"
 LOGGER = logging.getLogger(__package__)
 SERVERS = {
     "na": "https://fleet-api.prd.na.vn.cloud.tesla.com",
diff --git a/tesla_fleet_api/teslafleetapi.py b/tesla_fleet_api/teslafleetapi.py
index ad3c269..b877dc8 100644
--- a/tesla_fleet_api/teslafleetapi.py
+++ b/tesla_fleet_api/teslafleetapi.py
@@ -4,11 +4,11 @@
 from typing import Any, Awaitable
 from os.path import exists
 import aiohttp
+import aiofiles
 
 # cryptography
-from cryptography.hazmat.primitives.ciphers.aead import AESGCM
 from cryptography.hazmat.primitives.asymmetric import ec
-from cryptography.hazmat.primitives import hashes, serialization
+from cryptography.hazmat.primitives import serialization
 from cryptography.hazmat.backends import default_backend
 
 from .exceptions import raise_for_status, InvalidRegion, LibraryError, ResponseError
@@ -30,7 +30,7 @@ class TeslaFleetApi:
     session: aiohttp.ClientSession
     headers: dict[str, str]
     refresh_hook: Awaitable | None = None
-    _private_key: ec.EllipticCurvePrivateKey
+    _private_key: ec.EllipticCurvePrivateKey | None = None
 
     def __init__(
         self,
@@ -161,8 +161,8 @@ async def products(self) -> dict[str, Any]:
             "api/1/products",
         )
 
-    def private_key(self, path: str = "private_key.pem") -> ec.EllipticCurvePrivateKey:
-        """Create or load the private key."""
+    async def get_private_key(self, path: str = "private_key.pem") -> ec.EllipticCurvePrivateKey:
+        """Get or create the private key."""
         if not exists(path):
             self._private_key = ec.generate_private_key(
                 ec.SECP256R1(), default_backend()
@@ -173,16 +173,15 @@ def private_key(self, path: str = "private_key.pem") -> ec.EllipticCurvePrivateK
                 format=serialization.PrivateFormat.TraditionalOpenSSL,
                 encryption_algorithm=serialization.NoEncryption(),
             )
-            with open(path, "wb") as key_file:
-                key_file.write(pem)
-            return self._private_key
+            async with aiofiles.open(path, "wb") as key_file:
+                await key_file.write(pem)
         else:
             try:
-                with open(path, "rb") as key_file:
-                    key_data = key_file.read()
-                    value = serialization.load_pem_private_key(
-                        key_data, password=None, backend=default_backend()
-                    )
+                async with aiofiles.open(path, "rb") as key_file:
+                    key_data = await key_file.read()
+                value = serialization.load_pem_private_key(
+                    key_data, password=None, backend=default_backend()
+                )
             except FileNotFoundError:
                 raise FileNotFoundError(f"Private key file not found at {path}")
             except PermissionError:
@@ -191,4 +190,4 @@ def private_key(self, path: str = "private_key.pem") -> ec.EllipticCurvePrivateK
             if not isinstance(value, ec.EllipticCurvePrivateKey):
                 raise AssertionError("Loaded key is not an EllipticCurvePrivateKey")
             self._private_key = value
-            return self._private_key
+        return self._private_key
diff --git a/tesla_fleet_api/vehiclesigned.py b/tesla_fleet_api/vehiclesigned.py
index f423101..ec3fcde 100644
--- a/tesla_fleet_api/vehiclesigned.py
+++ b/tesla_fleet_api/vehiclesigned.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 import base64
-from dataclasses import dataclass
 from random import randbytes
 from typing import Any, TYPE_CHECKING
 import time
@@ -155,7 +154,7 @@ def tag(
 class VehicleSigned(VehicleSpecific):
     """Class describing the Tesla Fleet API vehicle endpoints and commands for a specific vehicle with command signing."""
 
-    _key: ec.EllipticCurvePrivateKey
+    _private_key: ec.EllipticCurvePrivateKey
     _public_key: bytes
     _from_destination: bytes
     _sessions: dict[int, Session]
@@ -165,13 +164,13 @@ def __init__(
     ):
         super().__init__(parent, vin)
         if key:
-            self._key = key
+            self._private_key = key
         elif parent._parent._private_key:
-            self._key = parent._parent._private_key
+            self._private_key = parent._parent._private_key
         else:
             raise ValueError("No private key.")
 
-        self._public_key = self._key.public_key().public_bytes(
+        self._public_key = self._private_key.public_key().public_bytes(
             encoding=Encoding.X962, format=PublicFormat.UncompressedPoint
         )
         self._from_destination = randbytes(16)
@@ -201,7 +200,7 @@ async def _handshake(self, domain: int) -> None:
         vehicle_public_key = info.publicKey
 
         # Derive shared key from private key _key and vehicle public key
-        shared = self._key.exchange(
+        shared = self._private_key.exchange(
             ec.ECDH(),
             ec.EllipticCurvePublicKey.from_encoded_point(
                 ec.SECP256R1(), vehicle_public_key
@@ -215,8 +214,6 @@ async def _handshake(self, domain: int) -> None:
             delta=int(time.time()) - info.clock_time,
         )
 
-        print(self._sessions[domain])
-
     async def _sendVehicleSecurity(self, command: UnsignedMessage) -> dict[str, Any]:
         """Sign and send a message to Infotainment computer."""
         if DOMAIN_VEHICLE_SECURITY not in self._sessions: