title: Cryptanalysis of ciphertext using Java
body: <p>I'm looking for some ideas on an assignment. </p>
  
  <p>I have 7 ciphertext files, all of which are encrypted using the <strong>same symmetric</strong> key, which is <strong>3 characters long</strong> and is <strong>alphabetic</strong>. No encryption algorithm is provided but the specs state that it is a <strong>home-made algorithm</strong> and is <strong>naive</strong> (whatever that means). My objective is to decrypt these files. I'm merely looking for ideas on the attacks which I can carry out on these files.</p>
  
  <p>So far, I have done a frequency analysis, brute force attack to detect Ceasar Cipher, Krasinsky's method to detect Vigenere Cipher, Ciphertext XOR to detect a simple version of the stream cipher. I suspect that the files were encrypted using some mix of ciphers.</p>
  
  <p>By the way, the decrypted plaintext is supposed to contain just a plain message, but the ciphertext reveals the use of over 97 different ASCII symbols!</p>
  
  <p>Any general help, ideas or directions are greatly appreciated! Honestly, I'm not expected to decrypt these files, but then I might as well prove my professor wrong with your help. Thanks!</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>I'm looking for attacks on block or stream ciphers. At least thats what I suspect...</p>