How to: sftp server
goes roughly 700 MiB/s (slower than webdav and ftp)

> this is **not** [ftps](#ftp-server) (which copyparty also supports); [ftps](#ftp-server) is ftp-tls (think http/https), while **sftp** is ssh-based and (preferably) uses ssh-keys for authentication

the sftp-server requires the optional dependency [paramiko](https://pypi.org/project/paramiko/);
* if you are **not** using docker, then install paramiko somehow
* if you **are** using docker, then use one of the following image variants: `ac` / `im` / `iv` / `dj`

enable sftpd with `--sftp 3922` to listen on port 3922;
* use global-option `sftp-key` to associate an ssh-key with a user;
  * commandline: `--sftp-key 'david ssh-ed25519 AAAAC3NzaC...'`
  * config-file: `sftp-key: david ssh-ed25519 AAAAC3NzaC...`
* `--sftp-pw` enables login with passwords (default is ssh-keys only)
* `--sftp-anon foo` enables login with username `foo` and no password; gives the same access/permissions as the website does when not logged in

see the [sftp section in --help](https://copyparty.eu/cli/#g-sftp) for the other options