Recently stories about StegIbiza have been cropping up on various newsfeeds of mine. StegIbiza is a proposed system for hiding morse code messages in minute fluctuations of tempo in dance music – the proposal is that a computer analysis of a track would be able to decipher the message, although whether this is dependable in practice is yet to be seen.
The practice of hiding secret messages in plain sight, within music, pictures or text, is known as steganography (secret writing) a term coined by, and historically bound up with, the 15th century abbot Trithemius and his Steganographia: a curious mixture of occultism and cryptography. This work was written 1500, but not published until 1606, and in the interim its reputation made it highly sought-after – John Dee’s own 1591 transcription survives in the National Library of Wales.
Reading the StegIbiza paper prompted me to renew my acquaintance with some of the other key texts of the historical steganography genre, which have always intrigued me. Examples include Vigenere’s Traite des Chiffres (1586), and especially Giambattista Porta’s De Furtivis Literarum (1563), which contains many beautiful examples of the steganographic art:
However, it is Gustav Selenus’ Cryptomenytices Et Cryptographiae Libri IX (1624) which is best known to followers of Trithemius, since it explained and expanded on the mysterious ciphers of the first two books of the Steganographia – although a ‘key’ to the first two books had previously been circulating in manuscript (and was printed after the book itself), the third book had to wait more than 300 years to be cracked. It was while browsing through Selenus’ work again, that I noticed an intriguing cipher that mixes Trithemius’ aesthetic of daemonic magic with music:
This cipher is attributed to a certain Count who followed the example of Trithemius and ‘clothed the same […] in the cloak of magic.’ Selenus declares that each musical tone is governed by two angels, RE – for example – by Lofaresiel at some times, and Druziel at others. He then gamely describes a magic ritual, which involves reading the above invocation four times – once toward each cardinal point – after which ‘there is no doubt that you will find the angels obedient to your wishes, so that, with their help, though not a musician, you will suddenly become such, and there will come unbidden to your pen a melody…’
In true Trithemian style, the invocation actually conceals instructions on how to use the cipher itself. By removing the first and last letters that ‘pad’ each word, and then reading the leftover letters backward, it conceals the words:
literam denotant tertium
invenitur concurrenti spatio
notarum illarum in
nomen cujus angeli
illius notae duae semper
This clue leads the reader toward the realisation that the third letter in each angelic name is the important one, and pairs of notes associated with each name are the key to ciphering and deciphering the message. If we take only the third letter of each name, the table looks like this:
Selenus provides an example of some text ciphered with this means:
The notation conceals the message ‘Hiet dich for deinem Diener Hansen: Daner sol dich ber nacht erwirgen,’ and sounds like this:
Rendering the music into modern notation might help to illustrate the process of deciphering – we find the first tone in each pair in the lefthand column of the table, then read across the row until we reach the second tone:
The process can be seen to be quite straightforward, and will produce some pleasing (if rather unadventurous) pentatonic melodies. To add a bit more variation, Selenus also uses octave transpositions, and elsewhere adds counterpoint to the ciphered message.
To wrap up, here’s an extract from the first of John Dee’s Forty-Eight Enochian Calls, split into four voices and ciphered with Selenus’ method:
… and here is a little guitar composition. This uses Selenus’ angelic dyads to encode a sentence from the from the hymn to Saint Eustace in line A (‘vir magno Eustachio’), and the words ‘Eustace eustachio’ in line B.
Archive.org hosts a draft English translation of Selenus’ work, made in 1900 by John William Henry Walden, but which was never published. The presentation is quite rough and at times confusing, so best read alongside a scan of an earlier edition.