Embodiments may include systems and methods for authenticating a message between a transmitter and a receiver. An apparatus for communication may include a transmitter to transmit a message to a receiver via a physical channel coupling the transmitter and the receiver. The message may be transmitted via a plurality of transmission voltage levels varied from a plurality of nominal voltage levels on the physical channel. The transmitter may include a voltage generator to generate the plurality of transmission voltage levels varied in accordance with a sequence of voltage variations from the plurality of nominal voltage levels for the message. The sequence of voltage variations may serve to authenticate the message between the transmitter and the receiver. Other embodiments may be described and/or claimed.