This uses V3 with AUTHPRIV.
! Create ACL to restrict inbound SNMP requests to a host IP of 10.50.50.1
ip access-list standard SECURE_SNMP
permit host 10.50.50.1
! Create SNMP Group
snmp-server group GROUP-NMS01 v3 priv
! Create SNMP User and apply ACL
snmp-server user USER-NMS01 GROUP-NMS01 v3 auth md5 AUTHPASS1 priv aes 128 PRIVPASS1 access SECURE_SNMP
! Create SNMP host and associate user
snmp-server host 10.50.50.1 traps version 3 priv USER-NMS01
Here’s how it marries up:
As of 2020, AES 128 encryption is as high as PRTG can go.