Some devices use * and SNMP tools use an AES key extension algorithm implementation for 192 and 256 bit key length that was not specified in the IETF draft http://tools.ietf.org/html/draft-blumenthal-aes-usm-04. Instead those implementations use the key extension algorithm specified by http://tools.ietf.org/html/draft-reeder-snmpv3-usm-3desede-00. To use the latter non-standard protocol follow the steps below:
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Note: Standard and non-standard protocols cannot be used for the same SNMPv3 security Name concurrently.
* SNMP4J users reported that there are Cisco devices using the 3DES key extension also for AES.