Snmptrap

/tmp/snmptrapd.conf

createUser -e 0x8000000001020304 traptest SHA mypassword AES mypassword
authuser log traptest

snmptrapd -f -C -c /tmp/snmptrapd.conf -Le

snmptrap -v 3 -n "" -a SHA -A mypassword -x AES -X mypassword -l authPriv -u traptest -e 0x8000000001020304 127.0.0.1 0 iso.3.6.1.6.3.1.1.5.2

You must use engineids

https://networkengineering.stackexchange.com/questions/32310/how-to-receive-snmp-v3-traps-without-specific-enginedid
You cannot be authenticated as user for receiving traps if you don't specify the engineID.
See http://www.net-snmp.org/wiki/index.php/TUT:Configuring_snmptrapd_to_receive_SNMPv3_notifications

Get engineid for -e option 0x8000000001020304

tshark -V -i eth0 -f "host 10.x.x.x" -d tcp.port==162,snmp | grep -i msgAuthoritativeEngineID