@@ -310,10 +310,17 @@ chrome.certificateProvider.onSignDigestRequested.addListener(cackeySignMessage); } function cackeyInit() { var elementEmbed; + + /* Verify that we can register callbacks */ + if (!chrome.certificateProvider) { + console.error("This extension only works on ChromeOS!"); + + return; + } if (cackeyHandle != null) { return; }