diff --git a/src/Web/ActivityPub.hs b/src/Web/ActivityPub.hs
index d69ef3d..e544726 100644
--- a/src/Web/ActivityPub.hs
+++ b/src/Web/ActivityPub.hs
@@ -209,7 +209,7 @@ instance ActivityPub PublicKey where
             when (t /= ("Key" :: Text)) $
                 fail "PublicKey @type isn't Key"
         (host, id_) <- f2l <$> (o .: "@id" <|> o .: "id")
-        shared <- o .: (frg <> "isShared") .!= False
+        shared <- o .:? (frg <> "isShared") .!= False
         fmap (host,) $
             PublicKey id_
                 <$> o .:? "expires"