Digital Sign PDF File with PHP and laravel

Question

Hello i search a lot before make this question. I know there is a paied option to sign pdf setasign.com

I try to use php function:

openssl_pkcs7_sign( FULL_PATH . "/pdforiginal.pdf", //ORIGIANL PDF
                    FULL_PATH ."signedPDF.pdf", // SIGNED PDF
                    "file://" . FULL_PATH . "signing_cert.pem", 
                     array(  "file://" . FULL_PATH. "private_key.pem",""),array()); 

signing_cert.pem <- // I Dont understand what is this i just have private_key and public_key. I see some examples where people use private_key here.

My private key dont have password shoud i use blank "" or null ?

If anyone can give me little information about this topic would be really helpful.

Answer 1

I find the solution. I use FPDI library to open pdf and use tcpdf library to sign it. That makes the process really simple.

require_once('tcpdf_include.php');

require_once "fpdi.php";

$pdf = new FPDI('P', 'mm', 'A4'); //FPDI extends TCPDF

$pages = $pdf->setSourceFile('document.pdf');



/*
NOTES:
 - To create self-signed signature: openssl req -x509 -nodes -days 365000 -newkey rsa:1024 -keyout tcpdf.crt -out tcpdf.crt
 - To export crt to p12: openssl pkcs12 -export -in tcpdf.crt -out tcpdf.p12
 - To convert pfx certificate to pem: openssl pkcs12 -in tcpdf.pfx -out tcpdf.crt -nodes
*/

$certificate = 'file://data/cert/tcpdf.crt';

// set additional information
$info = array(
    'Name' => 'TCPDF',
    'Location' => 'Office',
    'Reason' => 'Testing TCPDF',
    'ContactInfo' => 'http://www.tcpdf.org',
    );

for ($i = 1; $i <= $pages; $i++)
    {
        $pdf->AddPage();
        $page = $pdf->importPage($i);
        $pdf->useTemplate($page, 0, 0);


        // set document signature
        $pdf->setSignature($certificate, $certificate, 'tcpdfdemo', '', 2, $info);      

}