Sanitized

<?php
require '../functions.php';
    #sanitize($_POST['email'])
    #Would return the sanitized version of the inputted email
    #Written by Zbee (zbee.me)
    function sanitize($sql, $htmlAllowed = false) {
        $sql = preg_replace("/(drop table|show tables|`|\*|--|\\\\)/i","",$sql);
        $sql = trim($sql);
        if ($htmlAllowed ==== false) { $sql = strip_tags($sql); } #Some areas might have HTML, I dunno
            $sql = addslashes($sql);
        return $sql;
    }

$username = sanitize($_POST['username']);
$email = sanitize($_POST['email']);
$password = hash("sha256", sanitize($_POST['password'])); #You need to be using a salt, bro
$activationString = generateActivationString();
mysql_query("INSERT INTO users (username,email,password, activation_string) VALUES('$username','$email','$password','$activationString')");

$to = $email;
$subject = 'Xeno Network Website Acount Activation';
$headers = 'From: noreply@xenominecraft.ga';
$body = 'You have registered an account on the Xeno Network Website.' . "\r\n" .
        '' . "\r\n" .
        'Click this link below to confirm your registration:' . "\r\n" .
  'http://www.xenominecraft.ga/activate/?confirm='.$activationString . "\r\n" .
  '' . "\r\n" .
  'If you believe that this is a mistake, contact the website administrator at:' / "\r\n" .
  'mailto://website@xenominecraft.ga' . PHP_EOL;

mail($to, $subject, $headers, $body);
?>