Trithemius Ave Maria

Trithemius' Ave Maria is a steganographic process invented by the benedictine monk Johannes Trithemius around 1518. It replaces each letter of the plaintext by a group of words which looks like a poem.

Encryption uses a correlation table between letters and portions of psalms. Trithemius wrote a book (Polygraphiae - Ioannes Trithemius) which contains a hundred pages with Latin words associated with a letter of the alphabet.

The first page contains the following associations:

The Latin alphabet does not have all the letters, there is no V or W replaced by U, there is no J, replaced by I, and so on.

Encryption consists in encoding each letter of the message with a word in the list, the result will resemble a prayer/litany in Latin.

Example: To encrypt DCODE, use a word for D: opifex or piissimus, same with C, O etc. and get the following poem: Opifex pius
Imperator piissimus
Dominus

It is possible to fill in the text with other words to better link each component.

The book of Trithemius is composed of several hundred words. dCode only handles the first page of this fully written Latin book here (link)

Decryption requires to find the correspondence of each word in the book Polygraphia from Trithemius.

Example: For the poem
Opifex pius
Imperator piissimus
Dominus
Search opifex which corresponds to D then pius for C etc.
The plain message is DCODE.

The cipher is composed of Latin words generally related to God.

The encrypted message is much longer than the plain text (since it replaces letters with words).

Johannes Trithemius (born in 1462) would have written Steganographia in 1499 but it would have only been published in the early 17th century.