PHP

Specify a Certificate for Encrypted Email

Demonstrates the Chilkat Email.AddEncryptCert method, which explicitly specifies a certificate to use when sending encrypted email. Call it once per recipient certificate; ClearEncryptCerts clears the list. This example loads a recipient certificate, registers it, and enables encrypted sending.

Background: When encrypting to multiple people, each recipient needs to be able to decrypt with their own private key. S/MIME handles this by encrypting the message's one-time content key separately under each recipient's public certificate and including all of those wrapped keys in the message. AddEncryptCert is how you build that recipient list — one call per certificate — giving explicit control over exactly whose certificates are used rather than relying on automatic lookup.

Chilkat PHP Downloads

Download Chilkat for PHP

Chilkat2 PHP

<?php

use Chilkat2\Cert;
use Chilkat2\Email;

// Demonstrates the AddEncryptCert method, which explicitly specifies a certificate for
// sending encrypted email.  Call it once per recipient certificate.  Use ClearEncryptCerts
// to clear the list.

$email = new Email();
$email->Subject = 'Encrypted email';
$email->Body = 'Encrypted to the specified recipient certificate(s).';
$email->From = 'alice@example.com';
$email->AddTo('Bob', 'bob@example.com');

// Load a recipient certificate (public key) and add it to the encryption cert list.
$cert = new Cert();
try {
    $cert->LoadFromFile('qa_data/certs/recipient.cer');

    $email->AddEncryptCert($cert);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Request encrypted sending.
$email->SendEncrypted = true;

echo "Added the recipient's encryption certificate.\n";

// Note: The path "qa_data/certs/recipient.cer" is a relative local filesystem path,
// relative to the current working directory of the running application.