Does this mean that legions of peace-loving Trance fans could be soon be subliminally turned into robotic killing machines?

Probably not. However, the technology to hide messages in music continues to develop.

The idea of using music to send messages has a long history.

The German Benedictine monk Johannes Trithemius is widely credited with founding the discipline in the 16th century. And various others have run with the idea, with techniques such as mapping notes to letters (developed by the 17th-century German priest Gaspar Schott). More recently, cryptographers have developed a wide range of electronic techniques for hiding messages in digital music.

So it’s easy to imagine that the options for developing new forms of musical steganography have been exhausted.

Not so. Today, Krzysztof Szczypiorski at the Warsaw University of Technology in Poland reveals an entirely new form of musical steganography that he developed specifically for Ibiza dance-club music. The new method exploits the trance-like rhythms that this kind of music is famous for.

Ibiza is one of several Balearic islands that sit some 100 miles off the coast of Spain in the Mediterranean Sea. It is famous partly for its beautiful towns and villages but mainly for its nightlife and the electronic music that has evolved in clubs and beach raves. The music is characterized by a strong trance-like beat that encourages dancing—a beat that moves the feet!

Szczypiorski’s technique is to vary the tempo of the beat in a way that encodes information. But any changes have to be too subtle for human listeners to notice.

This kind of modification is possible because of modern digital audio workstations that allow various elements of compositions to be manipulated. For example, DJs often alter the tempo of music to mix it together, a particular feature of the Ibiza music scene.

Szczypiorski began by developing a simple Morse-like code in which he could spell out a series of dots and dashes to send messages. To indicate a dash, he speeds up the tempo for a single beat; to indicate a dot, he slows it down.


Read the full story at Technology Review

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