System and method for preventing replay attacks in wireless communication

Abstract

A method and apparatus for confirming the identity of a mobile station in a communication network. A mobile station transmits a security value to obtain access to the network. The system authenticates the mobile station prior to granting it access to the network. The system performs an additional procedure before granting access to the system if the security value sent by the mobile station matches a previously transmitted security value. Using this invention, the system prevents attempts of replay attacks by intruders.

We claim:  
     
         1 . A station within a communication network, the station comprising: 
 a receiver which receives transmissions from at least one mobile station operating within the range of the station;    a comparator which compares a first received transmission and a second received transmission, wherein the first received transmission and the second received transmission each carries authentication information of a mobile station in response to a challenge sent by the station; and    a processor configured to process the authentication information in the first received transmission and the authentication information in the second received transmission and to re-challenge the mobile station that sent the second received transmission if the comparison shows that the authentication information of the second received transmission matches the authentication information of the first received transmission.    
     
     
         2 . A method for confirming the identity of a mobile station within a communication network, the method comprising the steps of: 
 transmitting a challenge from a base station to the mobile station;    comparing a first received transmission and a second received transmission at a base station, wherein the first received transmission and the second received transmission contain authentication information identifying the mobile station in response to the challenge; and    transmitting a re-challenge from the base station to the originator of the second received transmission if the comparison results indicate that the authentication information of the second received transmission matches the authentication information of the first received transmission.    
     
     
         3 . A system for authenticating a mobile station in a communication network, the system comprising 
 at least one base station which receives signals from the mobile station and authenticates the mobile station prior to granting access to the communication network, each base station configured to perform a unique challenge procedure if the mobile station attempts to access the communication network using a public security parameter that is the same as a public security parameter used in a previous attempt by a similarly-identified mobile station to access the network.    
     
     
         4 . The system of  claim 3 , wherein the public security parameter comprises at least a RAND.