Hidings secret messages within a body of work, such as a musical composition, is nothing new — people have been using the technique of steganography since the 16th century, when Benedictine monk Johannes Trithemius hid his treatise on cryptography within a book about magic. Since then the discipline has improved immensely with researchers now encoding messages inside the digital music.
Szczypiorski uses variations in tempo to encode secret messages in Ibiza dance-club music, a type of music originating in the Balearic islands that are known for its heavy, trance-like beat. He uses the tempo changes as a digital Morse code — speeding up the tempo for a dot and slowing it down for a dash. These tempo changes are then added to a song using software like Apple’s Logix X Pro and used to spell out words. It’s so easy to apply that Szczypiorski expects someone can easily create a software program that will introduce these tempo changes automatically.
The technique is so subtle that listeners cannot detect these tempo changes, hearing only the music itself at parties. When testing this method, Szczypiorski found he could alter the tempo by 2 percent without people, even trained musicians noticing the changes. “At this level, the experiment was stopped because the rest of the party did not care about the music,” Szczypiorski said to MIT Technology Review. Szczypiorski called his technique “StegIbiza” after the music’s Mediterranean origins.
