def server(ID, Y, SS, U, V): P = H(ID) y = big.from_bytes(Y) Q = ecp2.generator() P = y * P sQ = ECp2() if not sQ.fromBytes(SS): return (False, Fp12(), Fp12()) TU = ECp() if not TU.fromBytes(U): return (False, bytearray(0), bytearray(0)) TV = ECp() if not TV.fromBytes(V): return (False, bytearray(0), bytearray(0)) TU.add(P) # TU.affine() r = pair.double_ate(Q, TV, sQ, TU) r = pair.fexp(r) if r.isone(): return (True, bytearray(0), bytearray(0)) # failed - diagnose it E = r.toBytes() r = pair.e(Q, TU) F = r.toBytes() return (False, E, F)