Abstract: It is vitally important to generate keys and keep them secret in secure wireless communications. Due to the broadcast nature of wireless channels, secret key distribution is more vulnerable to attacks in wireless communication. An ingenious solution is to generate secret keys by using the multipath channel as a source of common randomness. To address the problems that the existing physical-based protocols have low key generation rate and high reliance on mobile nodes or environments, a fast secret key generation protocol with virtual channel approach was proposed by HUANG and WANG for static wireless networks. In this paper, we show that, in the presence of an eavesdropper with multiple antennas, the scheme does not improve the theoretical upper bound of the key generation rate with information-theory security. Thus, the protocol is not information-theory security.