To guarantee security and privacy in speech,
image and video transmission and archival applications, efficient bulk encryption
techniques are necessary which are easily implementable in soft- and hardware and are able
to cope with the vast amounts of data involved. Experience has shown that block-oriented
symmetric product ciphers constitute an adequate design paradigm for resolving this task,
since they can offer a very high level of security as well as very high encryption rates.
In this contribution we introduce a new class of computationally secure product ciphers
with excellent encryption performance in hard- and software which encrypt blocks of
plain-text by repeated intertwined application of substitution and permutation operations.
Permutations are induced by the highly unstable nonlinear dynamics of chaotic Kolmogorov
flows, while substitutions are implemented using add-with-carry or subtract-with-borrow
generators.