The application below acts as a simple interface to the CSU List-Serv, allowing users to subscribe/unsubscribe themselves without any manual intervention. The system provides a secure mechanism for users to unsubscribe themselves from a list by sending an e-mail with an encrypted, tamper-proof key that only works with the given address. It also makes use of Recaptcha Captcha ( in order limit spam to the CSU List-Serv.