ttalvitie
commented
2 years ago I really don't have experience with legacy iOS or Puffin, so it's hard to exactly understand what you want to do or know how to help you (hopefully someone else can). I gathered from Puffin Browser Wikipedia page that it renders the pages on a remote server hosted by CloudMosa. Using this kind of remote browser as a client for Browservice (which you presumably run locally?) seems very inefficient as all the UI updates and input goes through the latency between you and the CloudMosa servers twice. Maybe you should run some local browser on the iOS device instead? (Though I need to warn you that Browservice is not really optimized for touchscreen devices and you will have problems with using e.g. keyboard.)
If you really want to do this weird double-proxy setup with Puffin and Browservice, then there is indeed the issue of securely exposing your Browservice to the remote Puffin browser. Exposing Browservice to the public internet is not a good idea as it has no real encryption built-in. You can use a reverse proxy server to TLS encrypt the traffic and then use HTTP authentication (either the built-in HTTP authentication of Browservice or preferably using the authentication capabilities in the reverse HTTPS proxy); however, you really need to take care to do everything correctly to make it secure.
I know Puffin is essentially a Remote VM so is it possible to securely forward the port?