Symfony News

New in Symfony 4.4: Signing and Encrypting Email Messages

Contributed by
Sebastiaan Stok
in #30981.

Symfony 4.4 will be released in November 2019. This is the first article of the series that shows the most important new features introduced by this Symfony version.

The new Mailer and Mime components were introduced in Symfony 4.3 to replace the previous solution based on SwiftMailer. In Symfony 4.4 we've improved them with new features to allow signing and encrypting email messages using the S/MIME standard.

Signing a message improves its integrity because it includes a digital signature of the hash of the entire email contents, ensuring that the original contents haven't been modified:

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use Symfony\Component\Mime\Crypto\SMimeSigner;
use Symfony\Component\Mime\Email;

$email = (new Email())->from('...')->to('...')->html('...');

$signer = new SMimeSigner('/path/to/certificate.crt', '/path/to/certificate-private-key.key');
$signedEmail = $signer->sign($email);
// now use the Mailer to send this $signedEmail instead of the original $email

Encrypting a message improves its security because its contents, including any attachments, can only be read if you have the private key associated to the public key used to encrypt them:

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use Symfony\Component\Mime\Crypto\SMimeEncrypter;
use Symfony\Component\Mime\Email;

$email = (new Email())->from('...')->to('...')->html('...');

$encrypter = new SMimeEncrypter('/path/to/certificate.crt');
$encryptedEmail = $encrypter->encrypt($email);
// now use the Mailer to send this $encryptedEmail instead of the original $email

Read the Signing and Encrypting Messages article in the official Symfony documentation to learn more about this feature.