gistfile1.php

<?php

$oib = '11111111111';
$dt = new DateTime('now');
$datumVrijemeIzdavanjaRacuna = $dt->format('d.m.Y H:i:s'); /* use invoice created_at datetime here */
$brojcanaOznakaRacuna = '23'; /* 23/MAGE5/1 */
$oznakaPoslovnogProstora = 'MAGE5'; /* 23/MAGE5/1 */
$oznakaNaplatnogUredaja = '1'; /* 23/MAGE5/1 */
$ukupniIznosRacuna = '182.50';
 
$ZastKodUnsigned = '';
 
$ZastKodUnsigned .= $oib;
$ZastKodUnsigned .= $datumVrijemeIzdavanjaRacuna;
$ZastKodUnsigned .= $brojcanaOznakaRacuna;
$ZastKodUnsigned .= $oznakaPoslovnogProstora;
$ZastKodUnsigned .= $oznakaNaplatnogUredaja;
$ZastKodUnsigned .= $ukupniIznosRacuna;
 
$ZastKodSignature = null;
 
openssl_sign($ZastKodUnsigned, $ZastKodSignature, $privateKeyResource, OPENSSL_ALGO_SHA1);
 
$ZastKod = md5($ZastKodSignature);