Improving Service Credibility in Password Authentication Peer Service?

Two server password-based authentication protocols (Two-Server PAKE), where two servers co-operate to authenticate a client on the basis of Password only and if one server is compromised due to Insider Attack or Distributed Denial Of Service Attack (DDOS). In Asymmetric two-server PAKE protocol runs in series and only the front-end server and the client need to establish a secret session key. In Two-Server PAKE protocol has been symmetric is not efficient for practical use. So, a Symmetric Two-Server PAKE protocol which supports two servers to compute in parallel to authenticate a client by Encrypted key exchange(EKE) and meanwhile keeps efficiency for practical use. It requires only four communication rounds for the client and two servers mutually to authenticate and simultaneously to establish secret session keys.