[SNMP4J] Issue using AES 192

[Ronald Braswell]

I have successfully configured a USM user on a Cisco 2960-XR device with
'auth SHA KEY' and 'priv AES 128 KEY'.  (the KEY is a placeholder in this
email to represent the pass phrase) This works fine.

However, when I use 'auth SHA KEY' and 'priv AES 192 KEY'  I get the
following error:

1.  In onResponse(ResponseEvent evt):

     evt.getError() ->  Exception:   'Message processing model 3 returned
error:  Encryption error'

     This is due to the report response from the target device to a
get-request from the manager.

I am attaching a file from a Wireshark export showing two instances of this
behavior.   Note that after the initial get-request and report response,
each invocation of snmp.send() simply returns the 'Message processing model
3 returned error: Encryption error'  without sending a new get-request.

I suspect that this is an issue with the target device with AES 192 and AES
256.   But I am wondering if there might be something that I might try on
the manager side.

Ron