What is the SDMI challenge?
On September 6, 2000, SDMI issued “An Open Letter to the Digital Community,” inviting people to attempt to crack certain technologies they are considering for use in their system. They set up a web site where music samples and some other information could be downloaded to aid in analyzing the technologies. In the first round of the challenge, SDMI provided four “watermark” challenges and two “non-watermark” challenges, as described below. For each watermark challenge, three audio streams were presented: a reference stream in its original form, the same stream with a watermark, and a challenge stream, watermarked, with no corresponding reference stream. The challenge was to submit to the SDMI “oracle” (a Web site), a version of the challenge stream with the watermark removed but without degrading the perceived sound quality of the original stream. The oracle would respond by email, after several hours, with an “ACCEPT” message (if the watermark was removed without degrading the sound qu
