title: Substitution cipher decryption using letter frequency analysis for text without blanks and special characters
body: <p>I need to find the plain text for given cipher text. I also have statistics (in an Excel document) for the letters in the given language e.g. I have the frequencies of the letters and also of the digraphs. </p>
  
  <p>I tried this approach so far: I evaluated the frequency of each letter in the cipher text I received. Then I sorted the letters in descending order by their frequencies and mapped each letter with the corresponding letter from the Excel document. The problem with this approach is that it gives me some text that has no meaning at all. That is because my text is pretty small (only 1500 characters long).</p>
  
  <p>I considered doing some limited permutations, but I have no idea what could I use to evaluate how good some permutation is. I think a good evaluation function would solve my problem.</p>
  
  <p>Be aware that all special characters and white spaces are removed from the text. Also there are no numbers.</p>
  
  <p>Thank you in advance.</p>