This project is a wrapper of PHP-DKIM library as a component for usage in conjunction with Yii framework. Nthing new, just convenient.

While DKIM relies on cryptographic signatures, it is quite easy to configure but it requires the use of OpenSSL on the command line (from your web server or on any platform).

1. Extract yii-dkim from archive to your application's extension directory
2. Generate the RSA private key (in the example key size is 384 bits which is very small and not very secure): openssl genrsa -out key.priv 384
3. Generate the RSA public key from the new RSA private key: openssl rsa -in key.priv -out key.pub -pubout -outform PEM
4. Copy and paste the private & public keys into configuration of this component.
5. Configure the remaining items in component configuration
6. Configure the DNS zone file of your domain.

I prefer to keep dkim configuration in separate config/dkim.php file as it includes big chunks of text (RSA keys) that don't look pretty in main config:

<?php
// ...
	'components' => array(
		// ...
		'dkim' => include(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'dkim.php'),
		// ...
	)

And here is config/dkim.php file:

<?php
return array(
	'class' => 'ext.dkim.Dkim',
	'open_SSL_pub' => '...',	// Here comes public RSA key
	'open_SSL_priv' => '...',	// Enter private RSA key here
	'domain' => 'domain.com',	// Your domain
	'selector' => '...'		// DKIM record selector
);

The basic PHP-DKIM usage for an HTML e-mail is:

<?php
$sender = 'john@example.com';
$headers = "From: \"Fresh DKIM Manager\" &lt;$sender&gt>\r\n".
"To: $to\r\n".
	"Reply-To: $sender\r\n".
	"Content-Type: text/html\r\n".
	"MIME-Version: 1.0";
$headers = Yii::app()->dkim->add($headers,$subject,$body) . $headers;
$result = mail($to,$subject,$body,$headers,"-f $sender");

The core function is add() which generates the DKIM-Signature: heading (which must preceede the other headers)).

• DKIM standard
• A great article on delivering email, sent from code