<?php



namespace PayPal\Security;



/**

 * Class Cipher

 *

 * Helper class to encrypt/decrypt data with secret key

 *

 * @package PayPal\Security

 */

class Cipher

{

    private $secretKey;



    /**

     * Fixed IV Size

     */

    const IV_SIZE = 16;



    function __construct($secretKey)

    {

        $this->secretKey = $secretKey;

    }



    /**

     * Encrypts the input text using the cipher key

     *

     * @param $input

     * @return string

     */

    function encrypt($input)

    {

        // Create a random IV. Not using mcrypt to generate one, as to not have a dependency on it.

        $iv = substr(uniqid("", true), 0, Cipher::IV_SIZE);

        // Encrypt the data

        $encrypted = openssl_encrypt($input, "AES-256-CBC", $this->secretKey, 0, $iv);

        // Encode the data with IV as prefix

        return base64_encode($iv . $encrypted);

    }



    /**

     * Decrypts the input text from the cipher key

     *

     * @param $input

     * @return string

     */

    function decrypt($input)

    {

        // Decode the IV + data

        $input = base64_decode($input);

        // Remove the IV

        $iv = substr($input, 0, Cipher::IV_SIZE);

        // Return Decrypted Data

        return openssl_decrypt(substr($input, Cipher::IV_SIZE), "AES-256-CBC", $this->secretKey, 0, $iv);

    }

}

