encode / decode PHP array for URL travel

encodingarray.php

<?php
/**
	 *  Encodes data into an unsubscribe token
	 *  @param ARRAY $params contains: lead_id (INT ), list_ids (MIXED), email_id (INT)
	 *  @return INT $token
	 */
	public static function encode_unsubscribe_token( $params ) {

		if (isset($params['doing_wp_cron'])) {
			unset($params['doing_wp_cron']);
		}
		$json = json_encode($params);

		$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
		$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
		$encrypted_string =
			base64_encode(
				trim(
					mcrypt_encrypt(
						MCRYPT_RIJNDAEL_256, substr( SECURE_AUTH_KEY , 0 , 16 )  , $json, MCRYPT_MODE_ECB, $iv
					)
				)
			);

		$decode_test = self::decode_unsubscribe_token($encrypted_string);

		return  str_replace(array('+', '/', '='), array('-', '_', '^'), $encrypted_string);
	}

	/**
	 *  Decodes unsubscribe encoded reader id into a lead id
	 *  @param STRING $reader_id Encoded lead id.
	 *  @return ARRAY $unsubscribe array of unsubscribe data
	 */
	public static function decode_unsubscribe_token( $token ) {

		$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
		$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
		$decrypted_string =
			trim(
				mcrypt_decrypt(
					MCRYPT_RIJNDAEL_256 ,  substr( SECURE_AUTH_KEY , 0 , 16 )   ,  base64_decode( str_replace(array('-', '_', '^'), array('+', '/', '='), $token ) ) , MCRYPT_MODE_ECB, $iv
				)
			);

		return json_decode($decrypted_string , true);

	}