Error bursts are randomized by an interleaver which makes use of "set leaders" to generate permutation indices. The permutation indices are used to route bits from initial positions in an input bit stream to re-arranged or randomized positions in an output bit stream. When the output bit stream is then transmitted and subsequently received by a de-interleaver which returns the received bits to their initial, pre-randomized positions, the resulting received signal has an acceptable bit error rate.