PHP

CMS Sign Hash

Demonstrates how to use the SignHashENC method to sign a pre-computed hash. This method creates a CMS signature (PKCS7 detached signature).

This example requires Chilkat v9.5.0.90 or later.

Chilkat2 PHP

<?php

use Chilkat2\Cert;
use Chilkat2\Crypt2;

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

$crypt = new Crypt2();

// Create the hash to be signed...
$crypt->HashAlgorithm = 'sha256';
$crypt->EncodingMode = 'base64';
$crypt->Charset = 'utf-8';
// Create the SHA256 hash of a string using the utf-8 byte representation.
// Return the hash as base64.
$base64Hash = $crypt->HashStringENC('This is the string to be hashed');

// Load a certificate for signing.
$cert = new Cert();
try {
    $cert->LoadPfxFile('qa_data/pfx/cert_test123.pfx', 'test123');

    $crypt->SetSigningCert($cert);

    // Sign the hash to create a base64 CMS signature (which does not contain the original data).
    // We can get the signature in a single line of base64 by specifying "base64", or
    // we can get multi-line base64 by specifying "base64_mime".
    $crypt->EncodingMode = 'base64_mime';
    $base64CmsSig = $crypt->SignHashENC($base64Hash, 'sha256', 'base64');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Note: In the above call to SignHashENC, the encoding of the returned CMS signature is specified by the EncodingMode property.
// However, the encoding of the passed-in hash is indicated by the 3rd argument.

echo 'CMS Signature: ', $base64CmsSig, "\n";