A secure discrete-time multiplexing technique is presented which uses a pseudorandom process with a fundamental cycle lengthN. The method can handleD ll Nsignal sequences of lengthM ll N. If all the signals have the same bandwidth, the multiplexed signal will have that bandwidth. WhenNis large the signal-to-noise ratios of the demultiplexed signals are high, even if the additive noise power is large. The demultiplexer most compute the same pseudorandom sequence that is used to encode the signals. Demultiplexing requires 3DMmultiplications andNDMadditions.