Note that auth token is opaque.

Change-Id: I788ab8c5be630dd818a9a442c487c3451029bf81
Test: N/A, comment-only change
Bug: 34985116
diff --git a/gatekeeper/1.0/types.hal b/gatekeeper/1.0/types.hal
index 8c184ee..59076e0 100644
--- a/gatekeeper/1.0/types.hal
+++ b/gatekeeper/1.0/types.hal
@@ -37,6 +37,6 @@
      * otherwise unused (0)
      */
     uint32_t timeout;
-    /* optional crypto blob */
+    /* optional crypto blob. Opaque to Android system. */
     vec<uint8_t> data;
 };