# Crack the Code

A sequence of letters appears on a screen, divided into blocks but unreadable at first glance. It is the *encoded* (*ciphered* or “*coded*“) form of an initially unknown text (“*plaintext*“). In other words, what you see is not the “plaintext”, but an encrypted or ciphertext, the “*ciphertext*“. The task of so-called *decoding* is to translate (*decipher*, i.e., translate) the ciphertext back into the corresponding plaintext. To do this, the code with which the plaintext was encoded, i.e. encrypted, must be “*cracked*“.

The ciphertexts that appear on the screen in EXPERIENCE LAND MATHEMATICS have been encoded according to a *monoalphabetic* code. This code assigns exactly one letter of the ciphertext alphabet to each letter of the alphabet. Such a code has been known and famous for over 2000 years as the so-called *Caesar cipher*. It bears the name of the Roman general and emperor, *Gajus Julius Caesar* (100–44 B.C.), who “*coded*” correspondence with his troops in this way. The alphabet of the ciphertext is created simply by shifting the order of the letters in the alphabet of the plaintext by a certain number of digits (*translation*). When shifted by four digits, the letters of the plaintext alphabet become the following ciphertext alphabet: