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DeCSS is a computer program capable of decrypting content on a DVD video disc encrypted using the Content-Scrambling System (CSS).
Origins and history
Technology and derived works When the release of the DeCSS source code made the CSS algorithm available for public scrutiny, it was soon found to be susceptible to a brute force attack quite different from DeCSS. The encryption is only 40 bit, and does not use all keys; a high-end home computer running optimized code is able to brute-force it in 24 hours quite easily. Programmers around the world created hundreds of programs equivalent to DeCSS, some merely to demonstrate the trivial ease with which the system could be bypassed, and others to add DVD support to open source movie players. The licensing restrictions on CSS make it impossible to create an open source implementation through official channels, and closed source drivers are unavailable for some operating systems, so some users need DeCSS to watch DVDs at all. See libdvdcss. Legal response In protest against legislation that prohibits publication of DeCSS code in countries that implement the WIPO Copyright Treaty (such as the United States' Digital Millennium Copyright Act), some have devised clever ways of distributing descriptions of the DeCSS algorithm, such as through steganography, through various Internet protocols, on t-shirts and in dramatic readings, as MIDI files, as a series of haiku poems•, and even as a so-called illegal prime number. However, the CSS algorithm seems to require more characters to describe in a computer programming language than the RC4 algorithm by RSA Data Security; one of the shortest implementations of the cipher (called "efdtt") is 434 bytes. Because of this, it has not been distributed by some of the more "inventive" methods used to distribute the RSA algorithm during the days of ITAR — it is not suitable for tattoos, email signatures, etc. As of 2006, DeCSS and several clones (which have not been specifically brought to court) can be readily obtained over the Internet. Some Linux distributions are able to install a DVD player incorporating a CSS implementation with a single command. The first legal threats against sites hosting DeCSS, and the beginning of the DeCSS mirroring campaign, began in about early November 1999 (Universal v. Reimerdes). As a response to these threats a program also called DeCSS but with an unrelated function was developed •. This program can be used for stripping Cascading Style Sheets tags from an HTML page. In one case, a school removed a student's webpage that included a copy of this program, mistaking it for the original DeCSS program, and received a great deal of negative media attention. The chief complaints against DeCSS (and similar programs) is that once the unencrypted source video is available in digital form, it can be copied without degradation, so DeCSS is associated with mass copyright infringement and a culture of sharing and distributing copyrighted information. However, lossless digital image copying of DVDs without decrypting them was already widespread before DeCSS, especially in East Asia. Furthermore, various DVD backup utilities that made use of "licensed" CSS decoding routines were also widely available. Notes | ||||||||||
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