diff --git a/src/Utils.js b/src/Utils.js
index c52bef2..9703bd9 100644
--- a/src/Utils.js
+++ b/src/Utils.js
@@ -1172,6 +1172,51 @@ utilities: {
 
 	return Proxmox.Utils.unknownText;
     },
+
+    render_u2f_error: function(error) {
+	var ErrorNames = {
+	    '1': gettext('Other Error'),
+	    '2': gettext('Bad Request'),
+	    '3': gettext('Configuration Unsupported'),
+	    '4': gettext('Device Ineligible'),
+	    '5': gettext('Timeout'),
+	};
+	return "U2F Error: " + ErrorNames[error] || Proxmox.Utils.unknownText;
+    },
+
+    // Convert an ArrayBuffer to a base64url encoded string.
+    // A `null` value will be preserved for convenience.
+    bytes_to_base64url: function(bytes) {
+	if (bytes === null) {
+	    return null;
+	}
+
+	return btoa(Array
+	    .from(new Uint8Array(bytes))
+	    .map(val => String.fromCharCode(val))
+	    .join(''),
+	)
+	.replace(/\+/g, '-')
+	.replace(/\//g, '_')
+	.replace(/[=]/g, '');
+    },
+
+    // Convert an a base64url string to an ArrayBuffer.
+    // A `null` value will be preserved for convenience.
+    base64url_to_bytes: function(b64u) {
+	if (b64u === null) {
+	    return null;
+	}
+
+	return new Uint8Array(
+	    atob(b64u
+		.replace(/-/g, '+')
+		.replace(/_/g, '/'),
+	    )
+	    .split('')
+	    .map(val => val.charCodeAt(0)),
+	);
+    },
 },
 
     singleton: true,