The Trithemius Cipher and the Tabula Recta – Let's Create and Break Them

#cryptology, #cryptography, #cryptanalysis

In this video, I introduce the "tabula recta" and the "Trithemius cipher". Both are shown and used in Johannes Trithemius famous book "Polygraphiae". The Trithemius cipher is one of the first polyalphabetic substitution ciphers, which is created using 24 shifted alphabets. It is much more secure than using a simple Caesar cipher, but it lacks of a key. If it is known, that the Trithemius cipher was used for encryption, the decryption is easily possible.

First, I give a short overview of Johannes Trithemius life. Trithemius was a famous Benedictine abbot, a polymath and cryptologist. After that, I introduce the tabula recta and the Trithemius cipher. Then, we create a tabula recta in CrypTool 2 as well as encrypt and decrypt using the Trithemius cipher. Finally, we break the Trithemius cipher using the Vigenère analyzer in CrypTool 2.

If you are interested in learning the basics of cryptology, you should also have a look at our video series about basics of cryptology – also for beginners: https://youtu.be/jbumW7Ym03o

You may download the latest version of CrypTool 2 from here: https://www.cryptool.org/en/ct2/downloads

Видео The Trithemius Cipher and the Tabula Recta – Let's Create and Break Them канала Cryptography for Everybody