title: Simple string encryption/decryption with a small resulting string
body: <p>I need to encrypt a string and then be able to decrypt it again.</p>
  
  <p>I implemented the solution <a href="https://stackoverflow.com/questions/10168240/encrypting-decrypting-a-string-in-c-sharp">here</a> and it works well, but the resulting string is not suitable as it needs to be simple and short enough for a user to use.</p>
  
  <p>I am encrypting incrementing database ID's (from 1) and there won't be more than 500. Ideally I'd like the encrypted string to be not more than 6 characters in length.</p>
  
  <p>Any ideas appreciated..</p>
  
  <p><strong>edit:</strong> It's a lengthy form which the user can resume at a later date with this generated string</p>