diff --git a/telethon/client/downloads.py b/telethon/client/downloads.py
index 6f1f0fdb..23441a18 100644
--- a/telethon/client/downloads.py
+++ b/telethon/client/downloads.py
@@ -5,6 +5,8 @@ import pathlib
 import typing
 import inspect
 
+from ..crypto import AES
+
 from .. import utils, helpers, errors, hints
 from ..requestiter import RequestIter
 from ..tl import TLObject, types, functions
@@ -17,7 +19,6 @@ except ImportError:
 if typing.TYPE_CHECKING:
     from .telegramclient import TelegramClient
 
-
 # Chunk sizes for upload.getFile must be multiples of the smallest size
 MIN_CHUNK_SIZE = 4096
 MAX_CHUNK_SIZE = 512 * 1024
@@ -376,7 +377,9 @@ class DownloadMethods:
             part_size_kb: float = None,
             file_size: int = None,
             progress_callback: 'hints.ProgressCallback' = None,
-            dc_id: int = None) -> typing.Optional[bytes]:
+            dc_id: int = None,
+            key: bytes = None,
+            iv: bytes = None) -> typing.Optional[bytes]:
         """
         Low-level method to download files from their input location.
 
@@ -415,6 +418,13 @@ class DownloadMethods:
                 The data center the library should connect to in order
                 to download the file. You shouldn't worry about this.
 
+            key ('bytes', optional):
+                In case of an encrypted upload (secret chats) a key is supplied
+
+            iv ('bytes', optional):
+                In case of an encrypted upload (secret chats) an iv is supplied
+
+
         Example
             .. code-block:: python
 
@@ -446,6 +456,8 @@ class DownloadMethods:
         try:
             async for chunk in self.iter_download(
                     input_location, request_size=part_size, dc_id=dc_id):
+                if iv and key:
+                    chunk = AES.decrypt_ige(chunk, key, iv)
                 r = f.write(chunk)
                 if inspect.isawaitable(r):
                     await r
diff --git a/telethon/client/uploads.py b/telethon/client/uploads.py
index 57262068..c5d2e3f4 100644
--- a/telethon/client/uploads.py
+++ b/telethon/client/uploads.py
@@ -8,6 +8,8 @@ import typing
 import inspect
 from io import BytesIO
 
+from ..crypto import AES
+
 from .. import utils, helpers, hints
 from ..tl import types, functions, custom
 
@@ -439,6 +441,8 @@ class UploadMethods:
             part_size_kb: float = None,
             file_name: str = None,
             use_cache: type = None,
+            key: bytes = None,
+            iv: bytes = None,
             progress_callback: 'hints.ProgressCallback' = None) -> 'types.TypeInputFile':
         """
         Uploads a file to Telegram's servers, without sending it.
@@ -476,6 +480,12 @@ class UploadMethods:
                 backward-compatibility (and it may get its use back in
                 the future).
 
+            key ('bytes', optional):
+                In case of an encrypted upload (secret chats) a key is supplied
+
+            iv ('bytes', optional):
+                In case of an encrypted upload (secret chats) an iv is supplied
+
             progress_callback (`callable`, optional):
                 A callback function accepting two parameters:
                 ``(sent bytes, total)``.
@@ -586,6 +596,10 @@ class UploadMethods:
                 # Read the file by in chunks of size part_size
                 part = stream.read(part_size)
 
+                # encryption part if needed
+                if key and iv:
+                    part = AES.encrypt_ige(part, key, iv)
+
                 # The SavePartRequest is different depending on whether
                 # the file is too large or not (over or less than 10MB)
                 if is_large: