Jon Lech Johansen, also known as DVD Jon, is a Norwegian programmer who has worked on reverse engineering data formats. He wrote the DeCSS software, which decodes the Content Scramble System used for DVD licensing enforcement. Johansen is a self-trained software engineer, who quit high school during his first year to spend more time with the DeCSS case. He moved to the United States and worked as a software engineer for about a year, from October 2005 until November 2006, whereupon he returned to Norway. Johansen moved back to the United States in June, 2007.