title: How would I reverse engineer a cryptographic algorithm?
body: <p>I wrote an application that encrypts text in this way:</p>
  
  <ol>
  <li><p>Get the input text</p></li>
  <li><p>Reverse the text</p></li>
  <li><p>Convert to hexadecimal</p></li>
  <li><p>XOR with a key</p></li>
  <li><p>Base64 encode</p></li>
  </ol>
  
  <p>Now, I didn't do a lot of encryption/encoding myself, so my question might sound stupid, but, say I get a file which has a content from the above algorithm and I didn't know about this algorithm. How would one start "breaking" the text, are there any guidelines, principals, rules to follow?</p>
  
  <p>My question is not tied to those 5 steps, that was a pure example.</p>
  
  <p>As a different example, take the text: A751CD9E1F99. How would I start investigating what this might mean?</p>