A communications system between a source and a destination includes a transmitter at the source and a communication connectivity. The transmitter comprises a preprocessor and a candidate envelope folder to provide M known a priori digital envelopes, M≥1. The preprocessor has N input ports and N output ports, N>M, performs at least one wavefront multiplexing (WFM) transform on N inputs received at the N input ports to generate N outputs at the N output ports. The preprocessor performs the at least one WFM transform by calculating, for each of the N outputs, a linear combination of the N inputs using one of the M digital envelopes such that a digital format of one of the N outputs appears to human sensors as having features substantially identical to a digital format of the one of the M digital envelopes.