Perl

Add a Detached Signature with a Separate Private Key

Demonstrates the Chilkat Mime.AddDetachedSignaturePk method, which creates a detached signature using a signer certificate and its separately supplied private key. The first argument is the Cert and the second is the PrivateKey.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Sometimes the certificate and its private key live apart — a .cer alongside a PEM key file, for instance — rather than bundled in a single PFX. This method pairs them explicitly for signing, whereas AddDetachedSignature expects a Cert that already provides its key. The result is the same multipart/signed message.

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Chilkat2 Perl

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;
}

# Load the certificate and its private key separately.
my $cert = Chilkat2::Cert->new;
$success = $cert->LoadFromFile('qa_data/signer.cer');
if (!$success) {
    print $cert->LastErrorText, "\n";
    exit;
}

my $privKey = Chilkat2::PrivateKey->new;
$success = $privKey->LoadPemFile('qa_data/signer_privkey.pem');
if (!$success) {
    print $privKey->LastErrorText, "\n";
    exit;
}

# Create a detached signature when the certificate and private key are supplied separately.  The
# 1st argument is the signer certificate and the 2nd is its private key.
$success = $mime->AddDetachedSignaturePk($cert, $privKey);
if (!$success) {
    print $mime->LastErrorText, "\n";
    exit;
}

$success = $mime->SaveMime('qa_output/signed.eml');
if (!$success) {
    print $mime->LastErrorText, "\n";
    exit;
}

print "Detached signature added.\n";