(more info begin)

encrypte mail openssl_pkcs7_sign

<?php
// the message you want to sign so that recipient can be sure it was you that
// sent it
$data = <<<EOD

You have my authorization to spend $10,000 on dinner expenses.

The CEO
EOD;
// save message to file
$fp = fopen("text.txt", "w");
fwrite($fp, $data);
fclose($fp);
// encrypt it
// Setup mail headers.
$headers = array("To" => "*************@gmail.com",
     "From" => "contact.atmoner@gmail.com",
     "Subject" => "A signed and encrypted message.");
     
$prepend = "file://";
openssl_pkcs7_sign(realpath(dirname(__FILE__)) . "/text.txt",
        realpath(dirname(__FILE__)) . "/enc.txt",
        $prepend . realpath(dirname(__FILE__)) ."/selfcert.pem",
        array($prepend . realpath(dirname(__FILE__)) ."/enc_key.pem", "abcdef"), $headers);


$data = file_get_contents("enc.txt");

// separate header and body, to use with mail function
//  unfortunate but required, else we have two sets of headers
//  and the email client doesn't decode the attachment
$parts = explode("\n\n", $data, 2);

// send mail (headers in the Headers parameter will override those
//  generated for the To & Subject parameters)
//if (isset($_GET['mail']))
mail("*****************@gmail.com", "test", $data, $parts[0]);
// sudo openssl req -x509 -days 365 -newkey rsa:1024 -keyout enc_key.pem -out selfcert.pem
// http://stackoverflow.com/questions/15237941/create-certificate-for-openssl-pkcs7-sign-in-php
?>