Just to clarify, a lot of people these days use a VPN-service to encrypt their surf. This is not the same thing - this is for outbound traffic (hide porno surfing or whatever people do in privacy
)
What you can do, if you skip to do the
easier port forwarding, is that you set up a VPN-server in your router (if it's capable).
Then you connect your phone to your VPN Server when your outside your home network and you can access your cameras/NVR.
The easiest way, sorry to say but will mention anyway.
If port forwarding and VPN server sounds to complicated you can look at a cloud service or a P2P solution. This is plug and play but unfavorable from a security and privacy perspective (my personal opinion!).
Edit: Depending on your camera model you can connect gDMSS or DMSS (successor of gDMSS) using P2P.
How to? Check the
wiki, direct link here:
DahuaWiki