MIME S/MIME Signing Algorithm Properties

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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.

use strict;
use warnings;
use Chilkat2;

my $mime = Chilkat2::Mime->new;
my $success = $mime->SetBodyFromPlainText('This message will be signed.');
if (!$success) {
    print $mime->LastErrorText, "\n";
    exit;
}

# 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(0);

# 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.
my $pfxPassword = 'myPfxPassword';
my $cert = Chilkat2::Cert->new;
$success = $cert->LoadPfxFile('qa_data/signer.pfx', $pfxPassword);
if (!$success) {
    print $cert->LastErrorText, "\n";
    exit;
}

# Create the detached signature using the algorithms configured above.
$success = $mime->AddDetachedSignature($cert);
if (!$success) {
    print $mime->LastErrorText, "\n";
    exit;
}

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