title: What is the difference between CURLOPT_SSLKEY and CURLOPT_SSH_PRIVATE_KEYFILE?
body: <p>I was looking at <a href="https://stackoverflow.com/questions/16342880/uploading-with-sftp-curlopt-sslkey-is-not-used">this question</a> and, to try to find the mistake, went to the <a href="http://php.net/manual/en/function.curl-setopt.php" rel="nofollow noreferrer">PHP manual</a> where I seen those 2 options :</p>
  
  <blockquote>
    <p><strong>CURLOPT_SSH_PRIVATE_KEYFILE</strong>   The file name for your private key. If
    not used, libcurl defaults to $HOME/.ssh/id_dsa if the HOME
    environment variable is set, and just "id_dsa" in the current
    directory if HOME is not set. If the file is password-protected, set
    the password with CURLOPT_KEYPASSWD. </p>
    
    <p><strong>CURLOPT_SSLKEY</strong>    The name of a file containing a private SSL key.</p>
  </blockquote>
  
  <p>OP of that question uses a <code>CURLOPT_SSH_PUBLIC_KEYFILE</code> so I guess it should uses a <code>CURLOPT_SSH_PRIVATE_KEYFILE</code> instead of a <code>CURLOPT_SSLKEY</code>, but I don't really know the difference between those options.</p>
  
  <p>So here comes my question :</p>
  
  <blockquote>
    <p>What is the difference between CURLOPT_SSLKEY and
    CURLOPT_SSH_PRIVATE_KEYFILE ?</p>
  </blockquote>