..
    Copyright 2020 NXP


.. _import-external-obj-prepare:

=================================================
 Import External Object Prepare
=================================================

Import External Object command allows the user to import
an external object wrapped with a secure ``ECKey_Auth``
context. A session is not required to execute this command,
the ``ECKey_Auth`` parameters are provided with the wrapped
WriteSecureObject command. The applet will use ``ECKey_Auth``
parameters and derive session keys to unwrap the command
and execute it. ``ImportExternalObject`` command works in its
own session. It will open an ``ECKey`` session, write the secure
object and close the session.


In this example, we prepare a complete raw APDU to be sent
to SE05x. A ``WriteSecureObject`` command needs to be prepared
which will be wrapped and sent as a part of ``ImportExternalObject``
command. For an example we are preparing ``WriteSymmKey`` command as :


.. literalinclude:: se05x_ImportExternalObjectPrepare.c
   :dedent: 4
   :language: c
   :start-after: /* doc:start:writesecureobjbuf */
   :end-before: /* doc:end:writesecureobjbuf */


.. literalinclude:: se05x_ImportExternalObjectPrepare.c
   :language: c
   :start-after: /* doc:start:createapdubuf */
   :end-before: /* doc:end:createapdubuf */

.. literalinclude:: se05x_ImportExternalObjectPrepare.c
   :language: c
   :start-after: /* doc:start:transformsapdubuf */
   :end-before: /* doc:end:transformsapdubuf */

.. literalinclude:: se05x_ImportExternalObjectPrepare.c
   :language: c
   :start-after: /* doc:start:transmitapdubuf */
   :end-before: /* doc:end:transmitapdubuf */

.. literalinclude:: se05x_ImportExternalObjectPrepare.c
   :language: c
   :start-after: /* doc:start:decryptsresponsebuf */
   :end-before: /* doc:end:decryptsresponsebuf */


You can call any of the ``WriteSecureObject`` API with your data
and create the buffer.


Building
=================================================

Build the project with the following configurations.

**se05x_ImportExternalObjectPrepare**

- ``Project = se05x_ImportExternalObjectPrepare``
- ``SCP=SCP03_SSS``
- ``SE05x_Auth=ECKey``


How to use
=================================================

Generate the raw APDU file by running the executable. Run
**se05x_ImportExternalObjectPrepare** as ::

    se05x_ImportExternalObjectPrepare.exe -keyid 0x7DA00003 -file eckey_ecdsa.der <portName>

where,

- *keyid* is the authentication keyId at which ECDSA public key is stored.
- *file* is the input ECDSA keypair file (in binary format)
- *portName* is the name of the port over which to connect (COMPORT in case running over VCOM)