koseven/system/config/credit_cards.php

<?php
/**
 * Credit card validation configuration.
 *
 * Options for each credit card:
 *  length - All the allowed card number lengths, in a comma separated string
 *  prefix - The digits the card needs to start with, in regex format
 *  luhn   - Enable or disable card number validation by the Luhn algorithm
 */
return [

	'default' => [
		'length' => '13,14,15,16,17,18,19',
		'prefix' => '',
		'luhn'   => TRUE,
	],

	'american express' => [
		'length' => '15',
		'prefix' => '3[47]',
		'luhn'   => TRUE,
	],

	'diners club' => [
		'length' => '14,16',
		'prefix' => '36|55|30[0-5]',
		'luhn'   => TRUE,
	],

	'discover' => [
		'length' => '16',
		'prefix' => '6(?:5|011)',
		'luhn'   => TRUE,
	],

	'jcb' => [
		'length' => '15,16',
		'prefix' => '3|1800|2131',
		'luhn'   => TRUE,
	],

	'maestro' => [
		'length' => '16,18',
		'prefix' => '50(?:20|38)|6(?:304|759)',
		'luhn'   => TRUE,
	],

	'mastercard' => [
		'length' => '16',
		'prefix' => '5[1-5]',
		'luhn'   => TRUE,
	],

	'visa' => [
		'length' => '13,16',
		'prefix' => '4',
		'luhn'   => TRUE,
	],

];