Disclosed is a vehicle rear seat whose seat back is foldable forwardly, comprising a seat back frame, a seat cushion frame, and a unit connected to the seat back frame and the seat cushion frame. Using the method, two devices on a network can exchange information using polynomials of a polynomial ring, authenticate each other using the exchanged information, and generate a shared key. The knob further carries a releasable latch that may extend radially outward relative to the knob to retain the indicator ring on the knob when the latch is in the latched position.