01 What is the Trithemius Cipher?

Tabula recta – Wikipedia

Johannes Trithemius (1462 – 1516) (actually: Johannes Heldenberg from Trittenheim) wrote the first printed book on cryptography, the “Polygraphiae libri sex” (Six Books on Polygraphy) in 1508, but it did not appear until 1518 after his death. In the fifth volume, he described, among other things, the encryption process using the tabula recta.

He proposed to encrypt the first letter of the message to be encoded using the first line of the tabula recta, the second with the second line, and so on.

This represents the first known polyalphabetic encryption method.

The tabula recta is also used in the Vigenère cipher proposed by the French cryptographer Blaise de Vigneère in 1585 or the Gronsfeld cipher proposed by Johann Franz Graf von Gronsfeld-Bronkhorst (1640 – 1719).