Interactive

The following link will take you to an on-line replica of the Enigma machine. To decode the message, set the letters at the top to "A A A" and type in the message below. If it won't let you type, change the last letter to "B" and then back to "A" and try again. The solution is a the bottom of the page.

In the simplest system of the Vigenère type the key is a word or a phrase which is repeated over and over again. The plaintext is encrypted using the table shown below. The cipher text letter is found at the intersection of the column headed by the plaintext letter and the row indexed by the key letter. To decrypt the plaintext letter is found at the head of the column determined by the intersection of the diagonal containing the cipher letter and the row containing the key letter.

Try to decrypt the following message. The solution is at the bottom of the page.

Plaintext:

Key:

Cipher text:

If you want to decode some messages using brain power alone, read the following directions and give some of the messages a try.

In cryptograms, one set of letters is substituted for another. To break the code, look for frequencies of certain letters or short groups. They are A, I, THE, AND. Try IT, TO, OF, and other common words when you find a group of two letters. When you find the substitute letter, apply it whenever the corresponding letter appears. Each cryptogram has its own code. The solutions are at the bottom of the page.

1. DUA UWBR GX XGTNBA: LKW NWD XKTA SHRXX KV KVA UGN, XKTA TKHA SHRXX KV DUA KDUAH UGN, RVZ DUAV LKW HKDRDA DUA EHKNX

2. MSB HBGMVUBNB VF FL HTJJBN GLM YBHTQFB VM STF T SQGNABN EBBM YQM YBHTQFB MSB FHVBGNVFM ZSL GTOBN VM HLQJNG'M HLQGM.

3. FQKRQI JGR BRIN CR TRELC JYCGREC F OFJKIL GFN HLRDFDOKZITYZIZ CR CIOO CGI CLECG.

1. The hula is simple: You put some grass on one hip, some more grass on the other hip, and then you rotate the crops.

2. The centipede is so called not because it has a hundred feet but because the scientist who named it couldn't count.

3. Anyone who goes to court without a lawyer has probably decided to tell the truth.

09/07/05

Decode a Message With the Enigma Machine