1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-----------------------------+-------------------------------+
|R|         Attribute Type      |            Length             |
+-+-------------+---------------+-------------------------------+
| Num Hash Algs |  ADN Length   |                               |
+---------------+---------------+                               +
~                Authentication Domain Name                     ~
+-------------------------------+-------------------------------+
| Hash Algorithm Identifier     |                               ~
+-------------------------------+                               +
~                     Certificate Digest                        ~
+---------------------------------------------------------------+