If you are using emacs under Microsoft Windows and you want to edit remote files through SSH, it’s possible to do it without using Cygwin. Tramp can use the tool “plink” from putty tools to do ssh.
What you need is to get “plink.exe” from the following page and get it into your $PATH, or choose the installer which will install all putty tools.
Then, edit your emacs file to add the following lines to tell it that you want to use plink when using tramp
(require 'tramp) (set-default 'tramp-default-method "plink")
Now, you can edit your remote files, but you will need to type your password. I think that in order to get password-less with ssh keys, you would need to use putty key agent.