SDMI Challenge Participants May Face DMCA DMCA4/21/2001; 11:25:48 AM "Everyone has probably forgotten the SDMI challenge to hackers to try to break a handful of proposed watermarking and "other" protection mechanisms? Well, it was recognised that a group of researchers at Princeton University broke all of the protection mechanisms and were due to publish a paper on at the 4th International Information Hiding Workshop (25-29 April) but have been threatened with the DMCA if they publish the results. So much for academic freedom, eh? SDMI seem particularly upset because one of the protection mechanims broken in the paper, The Verance Watermark, is currently used for DVD-Audio and SDMI Phase I products. Oops. Somehow, a copy of the threatening letter and the full paper entitled "Reading Between the Lines: Lessons from the SDMI Challenge" has appeared on John Young's excellent Cryptome site. SMDI's urge to "withdraw the paper submitted for the upcoming Information Hiding Workshop, assure that it is removed from the Workshop distribution materials and destroyed, and avoid a public discussion of confidential information." seems a little weak now...."If you have a background in signal processing, you'll be able to follow the paper. What's amazing is that for three of the four, I'd say the attacks were trivial... one of the solutions was to shift the entire piece of music by one quarter tone, doable with standard software (and there's free software that can do this). That's the kind of thing somebody with no clue about the details of signal processing would try, not a highly sophisticated attack requiring a PhD in the subject.I have a new theory: SDMI isn't trying to quash this paper because it will reveal how to break algorithms, they're trying to quash it because it's amazingly embarrassing.