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V. Mikhalev et al.
3.5 Conclusion and Future Directions
We have presented some advances in the design and security evaluations of some
contemporary symmetric encryption techniques which provide a good trade-off
between the implementation/execution complexity and the required security.
In one direction, we have demonstrated the use of keystream generators with
keyed update functions to provide the same security level at much smaller hardware
area costs. In particular, we have shown that the security limitations which were
believed to be imposed by the size of the state can be improved to offer a much
better trade-off between hardware requirements and security. In the other direction,
we have described the use of homophonic encoding for security enhancement of
certain randomized symmetric encryption schemes.
Also, we have discussed certain generic approaches for security evaluation
of the considered encryption schemes. The encryption schemes based on keyed
update functions were evaluated against a dedicated guess-and-determine attack.
The randomized encryption schemes were evaluated based on generic informationtheoretic and computational-complexity approaches. We believe that there is plenty
of room for further work in this area, and other innovative schemes should be
investigated. We have found that employment of keyed update functions and results
from coding theory are particularly promising ideas for the design of advanced
encryption schemes and we plan to explore them further in the near future.
Open Access This chapter is licensed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing,
adaptation, distribution and reproduction in any medium or format, as long as you give appropriate
credit to the original author(s) and the source, provide a link to the Creative Commons licence and
indicate if changes were made.
The images or other third party material in this chapter are included in the chapter’s Creative
Commons licence, unless indicated otherwise in a credit line to the material. If material is not
included in the chapter’s Creative Commons licence and your intended use is not permitted by
statutory regulation or exceeds the permitted use, you will need to obtain permission directly from
the copyright holder.
V. Mikhalev et al.
3.5 Conclusion and Future Directions
We have presented some advances in the design and security evaluations of some
contemporary symmetric encryption techniques which provide a good trade-off
between the implementation/execution complexity and the required security.
In one direction, we have demonstrated the use of keystream generators with
keyed update functions to provide the same security level at much smaller hardware
area costs. In particular, we have shown that the security limitations which were
believed to be imposed by the size of the state can be improved to offer a much
better trade-off between hardware requirements and security. In the other direction,
we have described the use of homophonic encoding for security enhancement of
certain randomized symmetric encryption schemes.
Also, we have discussed certain generic approaches for security evaluation
of the considered encryption schemes. The encryption schemes based on keyed
update functions were evaluated against a dedicated guess-and-determine attack.
The randomized encryption schemes were evaluated based on generic informationtheoretic and computational-complexity approaches. We believe that there is plenty
of room for further work in this area, and other innovative schemes should be
investigated. We have found that employment of keyed update functions and results
from coding theory are particularly promising ideas for the design of advanced
encryption schemes and we plan to explore them further in the near future.
Open Access This chapter is licensed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing,
adaptation, distribution and reproduction in any medium or format, as long as you give appropriate
credit to the original author(s) and the source, provide a link to the Creative Commons licence and
indicate if changes were made.
The images or other third party material in this chapter are included in the chapter’s Creative
Commons licence, unless indicated otherwise in a credit line to the material. If material is not
included in the chapter’s Creative Commons licence and your intended use is not permitted by
statutory regulation or exceeds the permitted use, you will need to obtain permission directly from
the copyright holder.