A communication device encrypts symbols at a physical layer in order to
improve encryption of data transmitted over a wireless link. A symbol
mapper of the communication device receives a bit stream comprising
multiple bits and maps the multiple bits to multiple symbols. An
amplitude and phase adjuster of the communication device receives the
multiple symbols and encrypts the symbols by applying at least one of a
phase shift and an amplitude adjustment to each symbol of the multiple
symbols to produce multiple encrypted symbols for transmission over a
wireless link. In another embodiment of the present invention, a
communication device is provided that is able to decrypt the encrypted
symbols by applying at least one of a phase shift and an amplitude
adjustment to each encrypted symbol that corresponds to a phase shift or
an amplitude adjustment applied to the symbol by a transmitting
communication device.