diff --git a/payload_constants.h b/payload_constants.h
new file mode 100644
index 0000000..4a4ec6f
--- /dev/null
+++ b/payload_constants.h
@@ -0,0 +1,21 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_PAYLOAD_CONSTANTS_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_PAYLOAD_CONSTANTS_H_
+
+#include <base/basictypes.h>
+
+namespace chromeos_update_engine {
+
+extern const char kBspatchPath[];
+extern const char kDeltaMagic[];
+
+// A block number denoting a hole on a sparse file. Used on Extents to refer to
+// section of blocks not present on disk on a sparse file.
+const uint64_t kSparseHole = kuint64max;
+
+};  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_PAYLOAD_CONSTANTS_H_