A method and apparatus for performing authentication in a communications system is provided. The method includes receiving a request for authentication from a server, the request for authentication including a first and a second random challenge, and comparing the first random challenge and the second random challenge. The method further includes denying the request for authentication in response to determining that the first random challenge is substantially the same as the second random challenge, and transmitting an encoded value to the server in response to determining that the first random challenge is different from the second random challenge, wherein the encoded value is generated based on the first and second random challenge and a key that is not shared with the server.