PHP

Create CMS Signed File (PDF) with Multiple Signing Certificates

See more Digital Signatures Examples

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.

Chilkat2 PHP

<?php

use Chilkat2\Cert;
use Chilkat2\Crypt2;

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

$crypt = new Crypt2();

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

$cert1 = new Cert();
try {
    $cert1->LoadPfxFile('qa_data/pfx/cert_test123.pfx', 'test123');

    $cert2 = new Cert();
    $cert2->LoadPfxFile('qa_data/pfx/test_secret.pfx', 'secret');

    // ------------ 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.
    $crypt->AddSigningCert($cert1);

    $crypt->AddSigningCert($cert2);

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

    $crypt->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.
    $crypt->CreateP7M($inFile, $p7sFile);

    // Verify the .p7s file and extract the original file from the .p7s.
    $extractedToFilePath = 'qa_output/sample.pdf';
    $crypt->VerifyP7M($p7sFile, $extractedToFilePath);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo "Success!\n";