Create a MRZ for ID cards

createmrz.php

#!/usr/bin/env php
<?php

// Line 1
$document_number = rand (0, 1000000000);        // 9 Digits
$country = 'XXX';                               // Unspecified
$document_type = 'I';                           // ID Card
$document_subtype = '<';                        // Generally 'D', or '<' for ID
$line1_optional = 'COMPANY';                    // Optional, 15 chars

// Line 2
$dob = '999999';                                // YYMMDD
$sex = '<';                                     // M, F, or <
$expiration = '222222';                         // YYMMDD
$nationality = 'XXX';                           // Country Code
$line2_optional = '';                           // Optional, 11 chars

// Line 3
$family_name = 'Smith';                         // Comes first
$given_names = array ('John', 'Alfred');        // Truncated down to a total of 30 characters

printf ("Document Number: %s\n", $document_number);


$line1 = sprintf ('%s%s%s%09s%d', $document_type, $document_subtype, $country, $document_number, checkDigit($document_number));
if (strlen ($line1) != 15) {
        sprintf ("Invalid input data.\n");
}

// Pad line out to 30 chars
$line1 = sprintf ('%15s%-15s', $line1, $line1_optional);
$line1 = str_replace (' ', '<', $line1);
if (strlen ($line1) != 30) {
        sprintf ("Invalid input data.\n");
}

// Encode line 2
$line2 = sprintf ('%6d%1d%1s%6d%1d%3s',
        $dob, checkDigit ($dob),
        $sex, $expiration, checkDigit ($expiration),
        $nationality);
$line2 = sprintf ('%15s%-11s', $line2, $line2_optional);
$line2 = str_replace (' ', '<', $line2);

// Generate the composite checksum
$composite_data = substr ($line1, 5, 25) . substr ($line2, 0, 7) . substr ($line2, 8, 7). substr ($line2, 18, 11);
$line2 .= checkDigit ($composite_data);

// Build line 3
$line3 = sprintf ('%s  %-30s', $family_name, implode (' ', $given_names));
$line3 = strtoupper (str_replace (' ', '<', $line3));
$line3 = substr ($line3, 0, 30);

printf ("%s\n", $line1);
printf ("%s\n", $line2);
printf ("%s\n", $line3);

function checkDigit ($input) {
        // MRZ checksums are weighted
        $weights = array (7, 3, 1);
        $sum = 0;

        // Split the string into it's respective characters
        $chars = str_split ($input);
        for ($i = 0; $i < strlen ($input); $i++) {
                $result = (getValue ($chars[$i]) * $weights[$i % 3]);
                // echo sprintf ("%s (%d) * %d = %d\n", $chars[$i], getValue ($chars[$i]), $weights[$i % 3], $result);
                $sum += $result;
        }

        return $sum % 10;
}

function getValue ($input) {
        $values = [
                '<' => 00, 'A' => 10, 'B' => 11, 'C' => 12, 'D' => 13,
                'E' => 14, 'F' => 15, 'G' => 16, 'H' => 17, 'I' => 18,
                'J' => 19, 'K' => 20, 'L' => 21, 'M' => 22, 'N' => 23,
                'O' => 24, 'P' => 25, 'Q' => 26, 'R' => 27, 'S' => 28,
                'T' => 29, 'U' => 30, 'V' => 31, 'W' => 32, 'X' => 33,
                'Y' => 34, 'Z' => 35
        ];

        if (strlen ($input) != 1) {
                system ("Invalid character.\n");
                exit (1);
        }
        if (is_numeric ($input)) {
                return (int)$input;
        } else {
                if (isset ($values[$input])) {
                        return $values[$input];
                } else {
                        printf ("Invalid character '%s' detected.\n", $input);
                        exit (1);
                }
        }
}