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+Export/Import Credentials
+=========================
+
+Sometimes, one may need to export credentials (e.g., certificate and private key) from
+one machine, and import them into another machine.  This requires a secured container for
+sensitive information.  We define **SafeBag**, which contains both an NDN certificate
+(:doc:`version 2.0 <certificate-format>`) and the corresponding private
+key which is encrypted in `PKCS#8 format <https://tools.ietf.org/html/rfc5208>`_.
+
+The format of **SafeBag** is defined as:
+
+::
+
+    SafeBag ::= SAFE-BAG-TYPE TLV-LENGTH
+                  Certificate ; a data packet following certificate format spec
+                  EncryptedKeyBag ; private key encrypted in PKCS#8 format
+
+All TLV-TYPE codes are application specific:
+
++---------------------------------------------+-------------------+----------------+
+| TLV-TYPE                                    | Assigned code     | Assigned code  |
+|                                             | (decimal)         | (hexadecimal)  |
++=============================================+===================+================+
+| SafeBag                                     | 128               | 0x80           |
++---------------------------------------------+-------------------+----------------+
+| EncryptedKeyBag                             | 129               | 0x81           |
++---------------------------------------------+-------------------+----------------+