title: cURL for SFTP with private key authentication
body: <p>I need to upload files by SFTP from a PHP script. I think cURL is probably the way, as I have this available on the server.</p>
  
  <p>Has anyone got an example of how to use cURL for SFTP using identity key authentication?</p>
  
  <p>-- EDIT --</p>
  
  <p>I've just noticed that HTTP PUT might be an alternative, but how secure it that?</p>