I was presented with a birthday greeting that used a substitution cipher. The catch is that he substituted every character of the message including symbols and substituted lowercase letters with different symbols than uppercase. Since uppercase and symbols are probably low frequency, normal frequency counts probably work.

My challenge is finding an application or website that allows me to substitute more than 26 characters. I could use search and replace in a text editor but that gets really confusing fast. I have found several tools that assume all symbols stay the same and that everything is in upper or lowercase.

I want to solve this by hand, but how can I do so many substitutions without paper?

  • 1
    $\begingroup$ what's the problem with the search and replace? I think I'd use that, just write numbers separated with spaces or underscores so that you don't have overlappings $\endgroup$ Commented Mar 30, 2018 at 14:55
  • $\begingroup$ Has a useful answer been given? If so, please don't forget to $\color{green}{\checkmark \small\text{Accept}}$ it :) $\endgroup$
    – Rubio
    Commented Apr 2, 2018 at 4:17
  • $\begingroup$ I don't have an easy way to test Cryptool as I use Mac most of the time, however, I should have access to a PC for a few hours next week.In the meantime, I would like to leave this open in hopes of a Mac or web app being suggested. $\endgroup$ Commented Apr 3, 2018 at 17:39

1 Answer 1


You can use Cryptool!

It is a free application that can be downloaded here.

In the text options you can specify that you want to distinguish between upper and lower case characters.



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