Wireless Networks based on WIFI or WIMAX become popular and are used in many places as compliment network to wired LAN to support mobility. The support of mobility of clients, the continuous access anywhere and anytime make WLAN preferable network for many applications. However, there are some issues associated with the usage of WLAN that put some restriction on adapting this technology everywhere. These issues are related to using the best routing algorithm to achieve good performance of throughput and delay, and to securing the open access to avoid attacks at the physical and MAC layer. IEEE 802.1x, suggested a solution to address the security issue at the MAC layer and but there are varieties of implementations address this solution and they differ in performance. IEEE 802.1af tried to address other security issue remained at the MAC layer but it is still at early stage and need verification for easy deployment. In this paper a new technique for securing wireless network using fast token-based authentication has been invented to address the vulnerability inherited by the wireless network at the MAC layer using fast authentication process. This technique is based on an authentication server distributing a security token, public authentication key, and network access key parameter to eligible mobile client MCs during registration. All messages will be encrypted during registration using temporary derived token key, but it will use derived valid token key during authentication. Authenticated MCs will then use derived group temporal key generated from the network access parameter key to encrypt all messages exchanged over the wireless network. The token, the authentication key and the access network parameter key will be only distributed during registration. This makes the security parameters known only to authentication server, authenticator and MC. Hence, this technique will protect the wireless network against attack since attackers are unable to know the token and other security keys. Moreover, it will avoid the exchange of public keys during authentication such as the one used in other existing technologies, and consequently speedup the authentication phase which is very critical to wireless technologies.