MIME S/MIME Signing Algorithm Properties

See more MIME Examples

Demonstrates the properties that control S/MIME signing: SigningAlg (the RSA signature scheme, PKCS1-V1_5 or RSASSA-PSS), SigningHashAlg (the message-digest algorithm), Micalg and Protocol (the micalg and protocol parameters of a multipart/signed Content-Type), and UseXPkcs7 (whether historical x-pkcs7 media-type names are used). The properties are configured before creating a detached signature.

<?php

use Chilkat2\Cert;
use Chilkat2\Mime;

$mime = new Mime();
try {
    $mime->SetBodyFromPlainText('This message will be signed.');

    // SigningAlg is the RSA signature scheme.  The default is PKCS1-V1_5; set RSASSA-PSS (or pss) for
    // RSASSA-PSS.
    $mime->SigningAlg = 'PKCS1-V1_5';

    // SigningHashAlg is the message-digest algorithm.  The default is sha256.
    $mime->SigningHashAlg = 'sha256';

    // Micalg and Protocol are the micalg and protocol parameters written into a multipart/signed
    // Content-Type header field.  They are normally set automatically, but can be controlled here.
    $mime->Micalg = 'sha-256';
    $mime->Protocol = 'application/pkcs7-signature';

    // UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
    $mime->UseXPkcs7 = false;

    // Load a signing certificate (with private key access) from a PFX.  The PFX password should come
    // from a secure source rather than being hard-coded.
    $pfxPassword = 'myPfxPassword';
    $cert = new Cert();
    $cert->LoadPfxFile('qa_data/signer.pfx', $pfxPassword);

    // Create the detached signature using the algorithms configured above.
    $mime->AddDetachedSignature($cert);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'Signed with SigningAlg=', $mime->SigningAlg, ' SigningHashAlg=', $mime->SigningHashAlg, "\n";