diff --git a/services/sync/BookmarksSyncService.js b/services/sync/BookmarksSyncService.js
index 999b29c70582..961a0176b7de 100644
--- a/services/sync/BookmarksSyncService.js
+++ b/services/sync/BookmarksSyncService.js
@@ -742,6 +742,11 @@ BookmarksSyncService.prototype = {
 
   _removeCommand: function BSS__removeCommand(command) {
     var itemId = this._bms.getItemIdForGUID(command.GUID);
+    if (itemId < 0) {
+      this._log.warn("Attempted to remove item " + command.GUID +
+                     ", but it does not exist.  Skipping.");
+      return;
+    }
     var type = this._bms.getItemType(itemId);
 
     switch (type) {
@@ -1339,6 +1344,21 @@ BookmarksSyncService.prototype = {
     this._log.warn("generator not properly closed");
   },
 
+  _encrypt: function BSS__encrypt(string, passphrase) {
+    let koFactory = Cc["@mozilla.org/security/keyobjectfactory;1"].
+      getService(Ci.nsIKeyObjectFactory);
+    let ko = koFactory.keyFromString(2, passphrase); // 2 is AES
+    let streamCipher = Cc["@mozilla.org/security/streamcipher;1"].
+      getService(Ci.nsIStreamCipher);
+    streamCipher.init(ko);
+    streamCipher.updateFromString(string);
+    return streamCipher.finish(true);
+  },
+
+  _decrypt: function BSS__decrypt(string, passphrase) {
+    // FIXME
+  },
+
   _onLogin: function BSS__onLogin(success) {
     this._loginGen.close();
     this._loginGen = null;