Laravel SFTP Connection Using Passphrase

       This is the stand way that I have been using to place a file in SFTP 

Storage::disk()->put($fileName, file_get_contents($storagePath . $fileName));

But I am facing a situation where for connection first I need pass the key-phrase and post that only SFTP will askfor user_id and password,

How can Is set this up for Jobs in Laravel, Using Laravel 5.1 (due to some issues cant upgrade but that's not the concern as of now)

My Configuration in Filesystem

'new_sftp' => [
        'driver'     => 'sftp',
        'host'       => 'homestead',
        'port'       => 22,
        'username'   => 'myuser',
        'password'   => 'mypass',
        'root'       => /myroot/folder,
        'privateKey' => '/home/myroot/myfile.pem',
        'password'   => 'mypassprase',
        'timeout'    => '300',
        'visibility' => 'public',
        'permPublic' => 0766,
    ],

via Chebli Mohamed