In recent years, the usage of IPTV (Internet Protocol Television) has been increased. The reason is a technological convergence of broadcasting and telecommunication delivering interactive applications and multimedia content through high speed Internet connections. The main critical point of IPTV security requirements is subscriber authentication. That is, IPTV service should have the capability to identify the subscribers to prohibit illegal access. Currently, IPTV service does not provide a sound authentication mechanism to verify the identity of its wireless users (or devices). This paper focuses on a lightweight authentication and key establishment protocol based on the use of hash functions. The proposed approach provides effective authentication for a mobile user with a RFID tag whose authentication information is communicated back and forth with the IPTV authentication server via IPTV set-top box (STB). That is, the proposed protocol generates user's authentication information that is a bundle of two public keys derived from hashing user's private keys and RFID tag's session identifier, and adds 1bit to this bundled information for subscriber's information confidentiality before passing it to the authentication server.