Step 1	Uα selects any temporary identity and password IDβ and pwβ. Uα computes the authentication request as follows. Tα denotes the current timestamp of Uα system, and RNα is a random nonce generated by Uα.
	$H_P{W}_{\beta }^{*}=h(p{w}_{\beta })$
	$A_{\beta }=h(I{D}_{\beta }\Vert H\_W_{\beta }^{*}\Vert x_s)\oplus h(K)$
	$DI{D}_{\beta }=h(I{D}_{\beta }\Vert H\_P{W}_{\beta }^{*}||x_s)\oplus h(x_s\Vert R{N}_{\alpha }\Vert T_{\alpha })$
	MUβ−G=h(Aβ∥xs∥RNα∥Tα)
	vβ=RNα ⊕ xs
	Uα sends the authentication request {DIDβ, MUβ−G, vβ, Tα} to GW.
Step 2	When GW receives the authentication request, GW checks if (TG−Tα) ≤ ΔT, where TG is the current timestamp of GW system. If (TG−Tα) ≤ ΔT, then the next step proceeds; otherwise, this phase is aborted.
Step 3	GW computes the following.
	RNα=vβ⊕ xs
	X*=DIDβ ⊕ h(xs∥RNα∥Tα)
	MUβ−G* = h((X* ⊕ h(K))∥xs∥RNα∥Tα)
	GW compares MUβ−G with MUβ−G*. GW regards {DIDβ, MUβ−G, vβ, Tα} as being sent from a legitimate user because MUβ−G = MUβ−G*.