Encryption of signals using data transpositions

The paper looks at the problem of signal encryption at two levels. First, it shows how Shannon´s results need to be modified to take into account signal distortions admissible at the receiver. In general, this reduces the effectiveness of encryption. Secondly, it considers the effectiveness of various transposition algorithms of encryption for intrablock scrambling. In particular, we propose a new, elegant algorthim called nonuniform transposition, and show that it is as effective as the earlier algorithms like pseudorandom and uniform addressings.