<?php

/**
 * JSON Web Token implementation, based on this spec:
 * http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06
 *
 * PHP version 5
 *
 * @category Authentication
 * @package  Authentication_JWT
 * @author   Neuman Vong <neuman@twilio.com>
 * @author   Anant Narayanan <anant@php.net>
 * @license  http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
 * @link     https://github.com/firebase/php-jwt
 */
class custom_encryption
{
	

	// Store cipher method 
	static private $ciphering = "AES-256-CBC"; 
	static private $key = "Awuc64pVpcB9xf"; 
	public static function encode($str)	
	{
		$string_to_encrypt = $str;
		// $string_to_encrypt = 'CJf1ac5a9c47284292d42eadc8f30b75df/20201015';
		// echo "Original String: " . $string_to_encrypt . "\n"; 
		// Use OpenSSl encryption method 
		$iv_length = openssl_cipher_iv_length(SELF::$ciphering); 
		$options = 0; 
		// echo '$iv_length-'.$iv_length;
		// Use random_bytes() function which gives 
		// randomly 16 digit values 
		// $encryption_iv = random_bytes($iv_length); 
		$encryption_iv = openssl_random_pseudo_bytes($iv_length); 
		// echo '$encryption_iv-'.$encryption_iv;

		// Alternatively, we can use any 16 digit 
		// characters or numeric for iv 
		$encryption_key = openssl_digest(SELF::$key, 'MD5', TRUE); 
		// echo '$encryption_key='.$encryption_key;

		// Encryption of string process starts 
		$encryption = openssl_encrypt($string_to_encrypt, SELF::$ciphering, 
				$encryption_key, $options, $encryption_iv); 

		// Display the encrypted string 
		// echo "Encrypted String: " . $encryption . "\n"; 
		return base64_encode($encryption.'.'.base64_encode($encryption_iv));

		// return base64_encode(openssl_encrypt($data, $this->method, $this->key, 0, $iv) . $this->separator . base64_encode($iv));
	}	


	public static function decode($str)
	{

		//echo 'Received-'.base64_decode($str);
		$received_data = explode('.',base64_decode($str));

		$str = $received_data[0];
		// Use OpenSSl encryption method 
		$iv_length = openssl_cipher_iv_length(SELF::$ciphering); 
		$options = 0;
		// echo '$iv_length-'.$iv_length;
		// Decryption of string process starts 
		// Used random_bytes() which gives randomly 
		// 16 digit values 
		// $decryption_iv = random_bytes($iv_length);
		$decryption_iv = base64_decode($received_data[1]);
		// echo '$decryption_iv-'.$decryption_iv; 

		// Store the decryption key 
		$decryption_key = openssl_digest(SELF::$key, 'MD5', TRUE); 
		// echo '$encryption_key='.$decryption_key;

		// Descrypt the string 
		$decryption = openssl_decrypt ($str, SELF::$ciphering, 
					$decryption_key, $options, ($decryption_iv)); 

		// Display the decrypted string 
		// echo "Decrypted String: " . $decryption; 
		return $decryption; 
	}

}