In a wireless communication system, a secure communication link is provided by selecting a decoy data signal for transmission, generating a precoding matrix from a message to be sent; and multiplying the decoy data signal by the precoding matrix to produce a precoded signal. A clean version of the decoy data may be transmitted to an intended receiver. The receiver can distinguish between the information-bearing precoding and the natural random channel distortions of the transmission medium to decrypt the information, while an eavesdropper would find it difficult to distinguish between the natural channel distortions and information-bearing precoding in the signals it receives.