diff --git a/src/future/oauth/PhutilOAuth1Future.php b/src/future/oauth/PhutilOAuth1Future.php
--- a/src/future/oauth/PhutilOAuth1Future.php
+++ b/src/future/oauth/PhutilOAuth1Future.php
@@ -227,9 +227,9 @@
     $consumer_secret = null;
     if ($this->consumerSecret) {
       $consumer_secret = $this->consumerSecret->openEnvelope();
+      $key = urlencode($consumer_secret).'&';
     }
 
-    $key = urlencode($consumer_secret).'&';
     if ($this->tokenSecret !== null) {
       $key .= urlencode($this->tokenSecret);
     }