Here is an example of how to use SNMPWALK with SNMPv3:
snmpwalk -v3 -l authPriv -u snmpv3user -a SHA -A "sdfs5dhudfsd=" -x AES -X "9Et+%ds!sefdsfsd=" 192.168.235.1-l authPriv → enables authentication + privacy
-u → specifies the SNMPv3 user used for the polling
-a → authentication algorithm & password
-x → encryption algorithm & password