Cryptography Reference
In-Depth Information
Chapter 3
Cryptanalysis in Detail
Our discussion of cryptography (i.e., the science of designing encryption algo-
rithms) and cryptanalysis have balanced out so far in this topic. From this
chapter onwards, we will systematically deepen the knowledge gained on
cryptanalysis. This is necessary because blindly trusting encryption algorithms
without knowing cryptanalytic methods is careless. Though we won't look at
modern
algorithms
yet, it doesn't mean that modern
software
doesn't play
a role! Moreover, looking at simpler methods makes it easier to understand
cryptanalysis.
It is required for this chapter to have read Chapter 2. I can still spare you the
mathematics to some extent. However, I will introduce three small C programs.
Even if you've never programmed you should try to understand the explanations
about these programs. You will learn interesting details about cryptanalysis.
The Web site to this topic allows you to try out several things discussed in this
chapter. Believe me, even if everything looks pretty simple in theory, there is
a fascinating experience to be had just in seeing how a program recovers your
really complicated and long password from apparent chaos in no time at all!
That gives you a real feeling for real dangers whilst having fun.
Though most of the programs discussed here were developed and tested under
UNIX, many of them are described generally so that they'll probably run on
any system as long as there is a C compiler. Check out Appendix A.1 for more
details.
