README

luhn-mod-n is a very simple solution to generate and verify luhn mod n checksums. Possible bases (value for n) are between 2 and 36. Luhn mod 10 is well known from the credit card number checksum. But also in different bases it can be useful to have this checksum functionality.

Example for base 2:

Input

1001001100101100000001011010010

Output (number with checksum)

10010011001011000000010110100100

Example for base 10:

Input

1234567890

Output (number with checksum)

12345678903

Example for base 16:

Input

499602d2

Output (number with checksum)

499602d2f

Example for base 36:

Input

kf12oi

Output (number with checksum)

kf12ois

Installing

You can use Composer to add the package to your project:

composer require stocker4all/luhn-mod-n

Usage example

<?php

use S4A\LuhnModN\LuhnModN;

include 'vendor/autoload.php';

// Base 10 example

$luhnModN = new LuhnModN();

$number = 1234567890;

// Generate checksum and return it concatenated to given number
$numberWithChecksum = $luhnModN->createChecksum($number, 10);

echo $numberWithChecksum."\n";

// Generate checksum and return only checksum
$onlyChecksum = $luhnModN->createChecksum($number, 10, false);

echo $onlyChecksum."\n";

// Verify the checksum
if ($luhnModN->hasValidChecksum($numberWithChecksum, 10)) {
    echo "Valid checksum\n";
}

This example will result in the following output:

12345678903
3
Valid checksum

Tests

Some very basic tests are provided in the tests/ directory. Run them with composer install --dev && vendor/bin/phpunit.

License

luhn-mod-n is licensed under MIT