This new post aims to expand an issue that was presented in class, cryptographer job, in this case the musical cryptogram.
The use of musical cryptogram has been much less than other uses of cryptography because of the difficulties of the environment where they have to hide the message, in this case the sound. But throughout history there are many examples of this use of sound, include compositions by JS Bach, Schumann, Brahms, or even modern composers of the twentieth century as Alban Berg or Oliver Messiaen. The best example is the use that gave the famous spy Mata Hari, who used this encryption to send secret messages to his allies.Due to this fact, this form of encryption is often referred to “Encrypting Mata Hari”.
All this technology is based on the association of certain sounds and notes with letters of the alphabet, so that the notes are part of a song, in turn, form the hidden message.Traditionally in many languages different notes have been associated with some letters of the alphabet, so for example the notes LA, would be A, the SI would be the B ect. With this method several composers recorded their names in the works that composed, for example BACH, which following the traditional German nomenclature corresponds to: B flat B, LA corresponds to A, DO is the C and, finally, the SI It represented by the letter H. Compounding that melody obtain the author’s name. Other composers have referred to this same case, “IMPROVISED WALTZ ON THE NAME OF BACH” of Poulenc. Generally this corresponds to a simple encryption encryption sustición, which is one of the simplest there, corrrespondiendo, for example to the next sample:
With this simple tactical wheel we could transmit messages in the form of innocent tonillos, for example:
However, this method can be complicated, and there are documented examples of codes that use both variations in tone and frequency using keys. That is, like the current encryption system is based on the famous public and private key, there are examples of similar constructions in the audio giving each person a melody, private “key” as well as a public. The value of this system, mainly as a curiosity, lies in the difficulty they may have the machines to identify slightly modified melodies, difficulty that we as humans do not possess.