Encryptions and secret messages

Object: ciphering wheel
Ciphering wheel, image taken from Giambattista Della Porta’s fundamental work De furtivis literarum notis, 1563
Deutsches Buch- und Schriftmuseum der Deutschen Nationalbibliothek Leipzig

Encryptions and secret messages

The cryptological search for the right code

… when something confidential had to be conveyed, he wrote in symbols, that is, he arranged the letters in such a way that no word could be read: To read them, one swapped the fourth letter, such as D for A, and on with the rest.

Gaius Suetonius Tranquillus on the Caesar’s cipher, De vita Caesarum, 120 CE

To understand a script, you must understand its code. You have to know what meaning is hidden behind a character and what rules a string of characters follows. Otherwise letters won’t reveal their meaning. Sometimes that is precisely the aim – with the aid of cryptology, the study of “secret words”, letters become coded secret messages. Encryption techniques stretch back to antiquity.

In the modern era, the ciphering wheel became a tool for assigning letters of the alphabet to secret characters. Since the First World War special cipher machines have been used in warfare. Today computers are used for data encryption. There are still some texts, such as the Voynich manuscript thought to date from the year 1500, which remain undeciphered to this day.