paste_login.php

<?php
include 'config.php';
$api_user_name      = $_POST['user'];
$api_user_password  = $_POST['password'];
$api_user_name      = urlencode($api_user_name);
$api_user_password  = urlencode($api_user_password);
$url                = 'http://pastebin.com/api/api_login.php';
$ch                 = curl_init($url);

curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, 'api_dev_key='.$api_dev_key.'&api_user_name='.$api_user_name.'&api_user_password='.$api_user_password.'');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_VERBOSE, 1);
curl_setopt($ch, CURLOPT_NOBODY, 0);

$response       = curl_exec($ch);

if(strncmp($response, "Bad API request", 15) != 0) {
    setcookie("api_user_key", $response, strtotime( '+30 days' ));
    echo 'Cookie set (Omnomnomnomnom)';
} else echo $response;

?>