diff --git a/src/activity.ts b/src/activity.ts
index 8a7ab62..14b22d0 100644
--- a/src/activity.ts
+++ b/src/activity.ts
@@ -293,7 +293,7 @@ export const userToPerson = (user: User) => {
         inbox: fillRoute("inbox", user.nickname),
         outbox: fillRoute("outbox", user.nickname),
         publicKey: {
-            id: id + "#main-key",
+            id: keyIdFromNickname(user.nickname),
             owner: id,
             publicKeyPem: user.public_key
         }