diff --git a/lib/src/client.dart b/lib/src/client.dart
index 3f280268..036d4572 100644
--- a/lib/src/client.dart
+++ b/lib/src/client.dart
@@ -1639,7 +1639,7 @@ class Client {
         "type": type,
         "content": message,
         "sender": this.userID,
-        "sender_keys": {"ed25519": fingerprintKey},
+        "keys": {"ed25519": fingerprintKey},
         "recipient": device.userId,
         "recipient_keys": {"ed25519": device.ed25519Key},
       };