toebes / ciphers

Cipher Generators

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Guidance.html suggestions

Agilus opened this issue · comments

I'm a big fan of the Guidance.html and have been pushing pretty hard here in Michigan to the extent that I can, for test writers to consult it. Now that regional competitions are beginning here, here are a couple of changes for your consideration (feel free to edit as you wish):

Timed Question:
I would leave the linked guidance to the Aristocrat/Patristocrat section, but change the text to say:
This should be an Easy or Medium Aristocrat without a hint, and should be designed to be solvable by approximately 1/3 of the teams within the 10 minutes given. Ensuring that the Timed Question is solvable in 10 minutes will help create variation in the scores and reduce the likelihood of ties.

Patristocrat/Xenocrypt:
The guidance for both of these suggests that they should always be encoded as a K1 or K2 to avoid making them too difficult. To support that, is that something you want to create a default behavior for or create a warning about in the question generator?

Baconian Cipher:
For the Words Baconian, is it suggested that a crib should be provided? There's a space for it in the generator and my students tend to complain if I don't provide one: "It could be literally anything." If it's best practice to include a crib for the Words Baconian, maybe adding a note to that effect in the Guidance would be helpful.

Nihilist Cryptanalysis:
I expect I'll add to this later, but if people are writing regional exams now, here is what I have learned so far that may help to guide difficulty, if you want to add any of this:
Setting Difficulty: In addition to the notes above, cryptanalysis makes Nihilist ciphers significantly more difficult due to the iteration and deduction required to solve it. As a result, these will be some of the most time-consuming problems on the test, and care should be taken to avoid making them too difficult. One factor for difficulty is the Block Size. A Block Size of 0 will make these easier to solve, while a Block Size that is nonzero and different from the keyword length will make these more difficult. Another factor for difficulty is the choice of crib. A longer crib makes the problem easier than a shorter crib, but note that too many duplicate letters within the crib will reduce the information that solvers have given to them. A third factor for difficulty is the relationship between the Keyword, the Polybius Key, and the Polybius table. If, after the Polybius table is constructed, the keyword draws primarily from the center values in the table, the problem will be more difficult. It is helpful to solvers if the keyword contains letters from a wider variety of locations in the Polybius table - both low values (letters which are also contained in the Polybius key) and high values (letters from the last row in the Polybius table), to help them analyze patterns in the cipher values. Lastly, the AutoSolver provides guidance on whether it is able to recover the keyword given the choice of keyword and crib provided, which can help guide the construction of these problems.

All of these changes have been implemented except for the one that has been branched off into issue #546 which should help ensure the right difficulty for these cipher types.