To guarantee security and privacy in image
transmission and archival applications, adequate efficient bulk encryption techniques are
necessary which are able to cope with the vast amounts of image 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 product cipher which encrypts large blocks of
plain-text (images) by repeated intertwined application of substitution and permutation
operations. While almost all of the current product ciphers use fixed (predefined)
permutation operations on small data blocks, our approach involves parameterizable (keyed)
permutations on large data blocks (whole images) induced by specific chaotic systems
(Kolmogorov flows). By combining these highly unstable dynamics with an adaption of a very
fast shift register based pseudo-random number generator we obtain a new class of
computationally secure product ciphers which are firmly grounded on systems theoretic
concepts, offering many features that make them superior to contemporary bulk encryption
systems when aiming at efficient image data encryption.