(PHP Extension) Create CMS Signed File (PDF) with Multiple Signing Certificates

Demonstrates how to sign a file by adding multiple signatures (multiple certificates). This example signs a PDF file to produce an output file that is a CMS signature wrapping the original PDF. (Note: This is different than modifying a PDF by injecting a signature into the PDF file format.)

Note: This example requires Chilkat v9.5.0.83 or greater.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

$crypt = new CkCrypt2();

// ------------ This example requires Chilkat v9.5.0.83 or greater.

$cert1 = new CkCert();
$success = $cert1->LoadPfxFile('qa_data/pfx/cert_test123.pfx','test123');
if ($success != true) {
    print $cert1->lastErrorText() . "\n";
    exit;
}

$cert2 = new CkCert();
$success = $cert2->LoadPfxFile('qa_data/pfx/test_secret.pfx','secret');
if ($success != true) {
    print $cert2->lastErrorText() . "\n";
    exit;
}

// ------------ This example requires Chilkat v9.5.0.83 or greater.

// Tell the crypt component to use both certificates for signing. 
// When we create the signature, it will be signed by both certificates.
$success = $crypt->AddSigningCert($cert1);
if ($success != true) {
    print $crypt->lastErrorText() . "\n";
    exit;
}

$success = $crypt->AddSigningCert($cert2);
if ($success != true) {
    print $crypt->lastErrorText() . "\n";
    exit;
}

// The CadesEnabled property applies to all methods that create PKCS7 signatures. 
// To create a CAdES-BES signature, set this property equal to true. 
$crypt->put_CadesEnabled(true);

$crypt->put_HashAlgorithm('sha256');

// We can sign any type of file, creating a .p7s as output.
// The .p7s contains the signature and also embeds the data of the file that is signed.
$inFile = 'qa_data/pdf/sample.pdf';
$p7sFile = 'qa_output/sample.pdf.p7s';

// Create the CAdES-BES attached signature, which contains the original data.
// Note: Chilkat's function naming is not accurate.  CreateP7M creates a PKCS7 signature where the signed file
// is contained within the signature.  CreateP7S creates a detached PKCS7 signature where the signed file
// is NOT contained within the signature.  We want the data to be contained in the signature, therefore
// we call CreateP7M even though we are naming our output file .p7s.
$success = $crypt->CreateP7M($inFile,$p7sFile);
if ($success == false) {
    print $crypt->lastErrorText() . "\n";
    exit;
}

// Verify the .p7s file and extract the original file from the .p7s. 
$extractedToFilePath = 'qa_output/sample.pdf';
$success = $crypt->VerifyP7M($p7sFile,$extractedToFilePath);
if ($success == false) {
    print $crypt->lastErrorText() . "\n";
    exit;
}

print 'Success!' . "\n";

?>