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Here are some hints and Tips on using the CryptoLeague tools and solving the puzzles.


Using the Tools:

  • Save a puzzle and then reopen it in the print view using the small printer icon next to the article.   Then you can print out a paper version of the puzzle which you can then play with while not at your computer.   Or you can use it to record a completed solution.

Solving the Puzzles:

  • All the puzzles are in capital letters.
  • Never get too fixated on one aspect of the problem.   Frequently step back and look at all the information that you have - the weaknesses in any cryptographic entity are usually a result of combinations of different bits of at-first apparently unrelated information.
  • You can attack a problem top-down or bottom-up.   In fact, you will need a combination of both.
  • Bottom-up solving involves the guessing of individual characters and your best friend here is a knowledge of the frequency distribution of your expected language.   Indeed frequency analysis can be used to identify what the plaintext language is likely to be.
  • It is also very helpful to know some basic patterns of your target language, e.g. in English, Q is almost always followed by U.
  • If you have whitespace then attacking the shortest words first makes sense, particularly if there are any one or two letter words.   A one letter word is either I or A.
  • Top-down solving involves trying to guess entire words, or even the entire text in one go.   For example, trying a three letter word out as "THE" can either quickly give you three letters or lead to some contradictions elsewhere.   In this approach, all the knowledge about the puzzle that you have is useful.   Especially author, or perhaps you suspect it might be a letter and begins with "Dear", or a date? etc.
  • Look for repeated words or phrases.
  • Don't ignore the alphabet.   Sometimes the actual cipher has structure in itself, e.g words buried in the alphabet or a simple rotation of letters.   If such weaknesses are there then don't miss them by concentrating only on the cryptogram text.   Sometimes the puzzle consists of finding the word buried in "ABCDEFGHIJKLMNOPQRSTUVWXYZ=>DFEXCALIBURGHJKMNOPQSTVWYZ"
  • Beware of tricks.   No one said that it had to be simple.   For example, a very simple trick that can throw frequency analysis out is to use any free cipher characters as duplicates for other plain characters.   e.g. if there are no Xs in the cryptogram then the cipher character X could be used as an additional representation for a plaintext E (most frequent letter in English) character.   Very simple, if you are looking out for it.
  • Beware of the spelling mistake - I don't guarantee that there aren't any...

Polyaphabetic Ciphers:

  • These are not yet in the tool as of the beta.   They consist of a family of ciphers using a set of alphabets, cycling through them as you encrypt the message.   e.g. with three alphabets, every third character is encrypted using the first alphabet, every third character starting with the second is encrypted with the second alphabet, etc.
  • These are not intended to be easy, nor do I expect people to solve these in minutes unless they can make an exceptionally lucky top-down guess.
  • Bottom-up solutions will need the texts to be longer too.
  • In principle, these need to be solved in several steps.   Firstly, we need the number of alphabets.   This will probably be available as a hint, but if not then you need to do the frequency analysis for each possibility until you find a number which is consistent with every n'th character having been encrypted with the same alphabet.
  • Once we know the number of alphabets, we are effectively solving n different puzzles bottom up, but one puzzle top down.  The tool will make this obvious by keeping track of which alphabet a given character is to be encrypted with.   I will probably also provide a way of doing the differentiated frequency analysis so that you can identify the numberof alphabets yourself.   Some colour coding in the tool is likely here.
Last Updated on Thursday, 07 October 2010 14:01
 
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