If we would like to use an "ecological" or at least the most-resource-saving protocol on Internet for exchanging text and files and which is secure, what could it be?
Gopher is quite simple, but has no security.
Gemini integrates with TLS, but doesn't allow to know the file's size before downloading. I think it is better to be able to choose to download according to the file size.
HTTPS allows maybe too much overhead and too much linked resources.
@DHeadshot It is an interesting idea, I think SFTP would be even a little bit better because the data goes into the same SSH connection.
FTPS?