diff --git a/monkey/monkey_island/cc/server_utils/encryption/key_based_encryptor.py b/monkey/monkey_island/cc/server_utils/encryption/key_based_encryptor.py
index a5cc1a6a7..8a46f2620 100644
--- a/monkey/monkey_island/cc/server_utils/encryption/key_based_encryptor.py
+++ b/monkey/monkey_island/cc/server_utils/encryption/key_based_encryptor.py
@@ -19,7 +19,8 @@ class KeyBasedEncryptor(IEncryptor):
     def __init__(self, key: bytes):
         """
         Initializes a KeyBasedEncryptor object
-        :param bytes key: The encryption key with which the object should be initialized
+        :param bytes key: The encryption key with which the object should be initialized.
+                          This should be a URL-safe base64-encoded 32-byte key.
         """
         self._key = key
         self._fernet_object = Fernet(self._key)