(PHP Extension) S/MIME Encrypt .eml without Sending

See more Email Object Examples

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux

<?php

include("chilkat.php");

$success = false;

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

$email = new CkEmail();

$success = $email->LoadEml('c:/temp/email/unencrypted.eml');
if ($success == false) {
    print $email->lastErrorText() . "\n";
    exit;
}

// The email content is encrypted using AES with a 256-bit key, operating in GCM mode, which provides authenticated encryption.
$email->put_Pkcs7CryptAlg('aes-gcm');
$email->put_Pkcs7KeyLength(256);
$email->put_OaepPadding(true);
$email->put_OaepHash('sha256');
$email->put_OaepMgfHash('sha256');

$cert = new CkCert();
$success = $cert->LoadFromFile('c/temps/cert/recipient.cer');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

$email->put_SendEncrypted(true);
$email->SetEncryptCert($cert);

$sbSmime = new CkStringBuilder();

// The mailman object applies the encryption by rendering the email according to the instructions (property settings) provided in the email object.
// No email is sent.
$mailman = new CkMailMan();
$success = $mailman->RenderToMimeSb($email,$sbSmime);
if ($success == false) {
    print $mailman->lastErrorText() . "\n";
    exit;
}

$success = $sbSmime->WriteFile('c:/temp/encryptedEmail.eml','utf-8',false);
if ($success == false) {
    print $mailman->lastErrorText() . "\n";
    exit;
}

print 'Success!' . "\n";

?>