I'm looking for a router that offers a demonstrably secure way to remotely access files on a hard drive attached via USB 3.
Many routers with USB ports allow you to attach a drive, and often offer an FTP server which, combined with DDNS, means you can access it remotely. However, FTP is not secure and for some reason, I've been unable to find any router which implements either FTP over TLS (FTPS) or FTP through SSH (SFTP).
Do you know of any (good!) consumer routers that do implement either an FTPS or SFTP server?
I say "demonstrably" above: I'm not keen on using the proprietary, built-in remote access functions that routers often come with, as these are notoriously not actually secure. Whereas SSH and TLS are known secure standards. I'm not looking to access nuclear launch codes, but equally I'm not looking for my files to be accessed by bots exploiting vulnerabilities in proprietary remote access implementations.
And when I say "securely access files" what I mean is end-to-end encrypted, i.e. no file or password is ever transmitted over the line in clear text, and no one could intercept the keys either (i.e. encrypted via some standard public key cryptography scheme).