diff --git a/include/tools_share/dualroot_oid.h b/include/tools_share/dualroot_oid.h
new file mode 100644
index 0000000..3e88a6d
--- /dev/null
+++ b/include/tools_share/dualroot_oid.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2020, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef DUALROOT_OID_H
+#define DUALROOT_OID_H
+
+/* Reuse the Object IDs defined by TBBR for certificate extensions. */
+#include "tbbr_oid.h"
+
+/*
+ * Platform root-of-trust public key.
+ * Arbitrary value that does not conflict with any of the TBBR reserved OIDs.
+ */
+#define PROT_PK_OID				"1.3.6.1.4.1.4128.2100.1102"
+
+#endif /* DUALROOT_OID_H */