Derived unique key per transaction

In cryptography, Derived Unique Key Per Transaction (DUKPT) is a key management scheme in which for every transaction, a unique key is used which is derived from a fixed key. Therefore, if a derived key is compromised, future and past transaction data are still protected since the next or prior keys cannot be determined easily. DUKPT is specified in ANSI X9.24 part 1.

Installation using Composer

$ composer require tonicforhealth/dukpt

Usage

<?php

use TonicForHealth\DUKPT\Device\PinEncryptionDevice;
use TonicForHealth\DUKPT\DUKPTFactory;

$cipherText = '160954FE1071D30C5CF260C5AC48EB5FBEFE37B32033E3B7EF693F8C6AB1BBD6276446FB3689728B926D923CD9ECCD522B6DE5850FD9AB2D7976D943C12CDC947E023098CAAE4F6D';

$device = new PinEncryptionDevice(new DUKPTFactory());
$device->load('0123456789ABCDEFFEDCBA9876543210', 'FFFF9876543210E00008');

$plainText = $device->decrypt($cipherText); // %B4124939999999990^TEST/TESTCARD^19129015432139614567891234567890?

Articles

• "How to decrypt magnetic card data with DUKPT" - Travis Hoffman