Cryptanalysis of Secure Key Exchange Protocol between STB and Smart Card in IPTV Broadcasting

In 2006, Yoon et al. [1] proposed a new secure key exchange protocol based on a one-way hash function and Diffie-Hellman key exchange algorithm for secure communication between STB and Smart Card in IPTV Broadcasting. In this paper, we show that Yoon et al.'s protocol is vulnerable to impersonation attack and can not achieve mutual authentication. Further, we recommend some modifications to the protocol to correct these security problems.