"""
SNMPv3: auth SHA, privacy AES128
++++++++++++++++++++++++++++++++

Send SNMP GET request using the following options:

* with SNMPv3, user 'usr-sha-aes', SHA authentication, AES128 encryption
* over IPv4/UDP
* to an Agent at demo.snmplabs.com:161
* for SNMPv2-MIB::sysDescr.0 MIB object

Available authentication protocols:

#. usmHMACMD5AuthProtocol
#. usmHMACSHAAuthProtocol
#. usmNoAuthProtocol

Available privacy protocols:

#. usmDESPrivProtocol
#. usm3DESEDEPrivProtocol
#. usmAesCfb128Protocol
#. usmAesCfb192Protocol
#. usmAesCfb256Protocol
#. usmNoPrivProtocol

Functionally similar to:

| $ snmpget -v3 -l authPriv -u usr-sha-aes -A authkey1 -X privkey1 \
|           -a SHA -x AES \
|           demo.snmplabs.com \
|           SNMPv2-MIB::sysDescr.0

"""#
from pysnmp.entity.rfc3413.oneliner.cmdgen import *

errorIndication, errorStatus, errorIndex, varBinds = next(
    getCmd(SnmpEngine(),
            UsmUserData('usr-sha-aes', 'authkey1', 'privkey1',
                        authProtocol=usmHMACSHAAuthProtocol,
                        privProtocol=usmAesCfb128Protocol),
            UdpTransportTarget(('demo.snmplabs.com', 161)),
            ContextData(),
            ObjectType(ObjectIdentity('SNMPv2-MIB', 'sysDescr', 0)))
)

if errorIndication:
    print(errorIndication)
elif errorStatus:
    print('%s at %s' % (
            errorStatus.prettyPrint(),
            errorIndex and varBinds[int(errorIndex)-1][0] or '?'
        )
    )
else:
    for varBind in varBinds:
        print(' = '.join([ x.prettyPrint() for x in varBind ]))