[ Home ] [ Up ] [ Shift Substitution Cipher ] [ Breaking a Shift Substitution Cipher ] [ MonoAlphabetic Substitution Cipher ] [ The Playfair Cipher ] [ The Vigenère Cipher ] [ Factorial Utilities ] [ Simulating a Coin Toss ] [ Sieve of Eratosthenes ] [ Modular Arithmetic ] [ Message Digests ]

Creating or Breaking a MonoAlphabetic Substitution Cipher

Below is an applet which helps you to create, from a specified plaintext, a ciphertext based a monoalphabetic substitution cipher, where each plaintext letter has a 1-to-1 mapping to its ciphertext letter.  You can also use the applet to try to break a ciphertext based on a monoalphabetic substitution cipher, by simply applying the reverse letter mapping (from ciphertext to plaintext).

Just click on its Start button to bring up the applet's frame:

Your browser does not have Java support. Please install the Java Plug-in.

Here's an image of what you should see:

If you don't see this, perhaps you don't have the Java Plug-in properly installed?

To create ciphertext, type your plaintext message in the upper text area, select the individual letter mappings, and click the Translate button.  The resulting ciphertext will appear in the lower text area.