Surgical attack

The surgical attack is the ultimate version of the directed attack. It requires an almost complete understanding of the inner workings of the marking scheme. This attack represents the case where one is actually able to recover the original song, by ``surgically'' removing only the part representing the mark from the marked version. The main advantage of finding such an attack is that all the problems related to the quality of the songs are gone. This attack can consequently be automated. Hence, with a surgical attack, one could code a filter that would automatically remove the mark of any song downloaded to his computer, thus defeating the whole purpose of the scheme.

We were able to mount random or directed attacks against all the schemes proposed by the SDMI, based on non-standard compression and non-linear time modifications. We were also able to perform an almost surgical attack on one of the scheme, which is the one we are going to present now.