diff --git a/proto/secrets.proto b/proto/secrets.proto
new file mode 100644
index 0000000..be98361
--- /dev/null
+++ b/proto/secrets.proto
@@ -0,0 +1,36 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file defines protobufs needed for handling Monorail secrets.
+
+syntax = "proto3";
+
+package monorail.secrets;
+
+
+// Next available tag: 7
+message ListRequestContents {
+  // The parent resource of the requested resources.
+  string parent = 1;
+  // The requested page size for listing the resources.
+  int32 page_size = 2;
+  // The requested sort order of the list of resources.
+  string order_by = 3;
+  // The query that may be used to filter which resources to show.
+  string query = 4;
+  // The resource names of projects to query within.
+  repeated string projects = 5;
+  // The string that may be used to filter which resources to show.
+  // See AIP-160.
+  string filter = 6;
+}
+
+
+// Next available tag: 3
+message PageTokenContents {
+  // The index of where the requested resource list should start.
+  int32 start = 1;
+  // An encrypted ListRequestContents message.
+  bytes encrypted_list_request_contents = 2;
+}