Sign Encrypted PDF Document
This PHP demo shows how to digital sign an already encrypted/protected PDF document (user-password:
topsecret; owner-password: owner).
It is not enough to authenticate at the initial document instance but the signer needs to be able to do this on an intermediate version, too.
How to authenticate against an existing security handler of a PDF document can be found in the manual of theSetaPDF-Core component.
PHP
<?php
use setasign\SetaPDF2\Core\Document;
use setasign\SetaPDF2\Core\SecHandler\SecHandlerInterface;
use setasign\SetaPDF2\Core\Writer\HttpWriter;
use setasign\SetaPDF2\Signer\Signature\Module\Pades as PadesModule;
use setasign\SetaPDF2\Signer\Signer;
// load and register the autoload function
require_once __DIR__ . '/../../../../../bootstrap.php';
$writer = new HttpWriter('topsecret.pdf');
$document = Document::loadByFilename(
$assetsDirectory . '/pdfs/tektown/Laboratory-Report-up=topsecret,op=owner.pdf',
$writer
);
// let's create an authentication callback
$authCallback = static function(SecHandlerInterface $secHandler) {
$secHandler->auth('owner');
};
// create a signer instance and pass the callback
$signer = new Signer($document, $authCallback);
// add a signature field
$field = $signer->addSignatureField();
// and define that you want to use this field
$signer->setSignatureFieldName($field->getQualifiedName());
$certificatePath = $assetsDirectory . '/certificates/setapdf-no-pw.pem';
// now create a signature module
$module = new PadesModule();
// pass the path to the certificate
$module->setCertificate('file://' . $certificatePath);
// set the path to the private key (in this demo the key is also saved in the certificate file)
$module->setPrivateKey('file://' . $certificatePath, '');
// sign the document with the module
$signer->sign($module);