To send email using PHP, you use the mail() function. This mail() function accepts 5 parameters as follows (the last 2 are optional).
<?php
mail($to,$subject,$message,$headers);
?>
mcrypt_encrypt : string mcrypt_encrypt ( string $cipher , string $key , string $data , string $mode [, string $iv ] );
Encrypts plaintext with given parameters
finally you can't send email from localhost.
