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Qrpff
qrpff is a Perl script created by Keith Winstein and Marc Horowitz of the MIT SIPB. It performs DeCSS in six or seven lines. The name itself is an encoding of "decss" in rot-13. The algorithm was rewritten 77 times to condense it down to six lines. In fact, two versions of qrpff exist: a short version (6 lines) and a fast version (7 lines). Both appear below. Short: #!/usr/bin/perl # 472-byte qrpff, Keith Winstein and Marc Horowitz # MPEG 2 PS VOB file -> descrambled output on stdout. # usage: perl -I :::: qrpff # where k1..k5 are the title key bytes in least to most-significant order s''$/=\2048;while()';s/ -HO-U_\$$&/g;s/q/pack+/g;eval Fast: #!/usr/bin/perl -w # 531-byte qrpff-fast, Keith Winstein and Marc Horowitz # MPEG 2 PS VOB file on stdin -> descrambled output on stdout # arguments: title key bytes in least to most-significant order $_='while(read+STDIN,$_,2048)';s/x/pack+/g;eval The fast version is actually fast enough to decode a movie in real-time. qrpff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keith Winstein
Keith Jonathan Winstein (born 1981) is a U.S. computer scientist and journalist. He is currently a professor at Stanford University. Previously, he was the Claude E. Shannon Research AssistantKeith Winstein and Faraz Najafi named recipients of 2012 Claude E. Shannon Research Assistantships RLE News Articles, 27 April 2012. Retrieved 2 May 2013. at the 's Networks and Mobile Systems group at the |
The Algorithm Auction
The Algorithm Auction is the world's first auction of computer algorithms. Created by Ruse Laboratories, the initial auction featured seven lots and was held at the Cooper Hewitt, Smithsonian Design Museum on March 27, 2015. Five lots were physical representations of famous code or algorithms, including a signed, handwritten copy of the original Hello, World! C (programming language), C program by its creator Brian Kernighan on dot-matrix printer paper, a printed copy of 5,000 lines of Assembly language, Assembly code comprising the earliest known version of Turtle Graphics, signed by its creator Hal Abelson, a necktie containing the six-line qrpff algorithm capable of decrypting content on a commercially produced DVD video disc, and a pair of drawings representing OkCupid's original Compatibility Calculation algorithm, signed by the company founders. The qrpff lot sold for $2,500. Two other lots were “living algorithms,” including a set of JavaScript tools for building applic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was officially changed to Raku in October 2019. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Raku, which began as a redesign of Perl 5 in 2000, eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from each other. The Perl languages borrow features from other programming languages including C, sh, AWK, and sed; They provide text processing facilities without the arbitrary data-le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIPB
The Student Information Processing Board (SIPB) is a student group at the Massachusetts Institute of Technology (MIT) that helps students access computing resources and use them effectively. History SIPB was founded in 1969 by Bob Frankston, Gary Gut, David Burmaster, and Ed Fox. At the time, computers in universities were still expensive resources reserved for funded research projects. Through an arrangement with the MIT administration, SIPB administered student accounts on university-owned computers. This allowed students access to MIT's timeshared computers when computers otherwise cost millions of dollars and were as big as an entire room. In 1983, MIT launched Project Athena, an initiative to create a distributed computing system for educational use. SIPB was instrumental in the creation of Project Athena and helped to provide MIT students with access to computing resources for independent projects. Project Athena led to several important Unix technologies such as X11, inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DeCSS
DeCSS is one of the first free computer programs capable of decrypting content on a commercially produced DVD video disc. Before the release of DeCSS, open source operating systems (such as Berkeley Software Distribution, BSD and Linux) could not play encrypted video DVDs. DeCSS's development was done without a license from the DVD Copy Control Association (CCA), the organization responsible for DVD copy protection—namely, the Content Scramble System (CSS) used by commercial DVD publishers. The release of DeCSS resulted in a Norwegian criminal trial and subsequent acquittal of one of the authors of DeCSS. The DVD CCA launched numerous lawsuits in the United States in an effort to stop the distribution of the software. Origins and history DeCSS was devised by three people, two of whom remain anonymous. It was on the Internet mailing list LiViD in October 1999. The one known author of the trio is Norway, Norwegian programmer Jon Lech Johansen, whose home was raided in 2000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ROT13
ROT13 ("rotate by 13 places", sometimes hyphenated ROT-13) is a simple letter substitution cipher that replaces a letter with the 13th letter after it in the alphabet. ROT13 is a special case of the Caesar cipher which was developed in ancient Rome. Because there are 26 letters (2×13) in the basic Latin alphabet, ROT13 is its own inverse; that is, to undo ROT13, the same algorithm is applied, so the same action can be used for encoding and decoding. The algorithm provides virtually no cryptographic security, and is often cited as a canonical example of weak encryption. ROT13 is used in online forums as a means of hiding spoilers, punchlines, puzzle solutions, and offensive materials from the casual glance. ROT13 has inspired a variety of letter and word games online, and is frequently mentioned in newsgroup conversations. Description Applying ROT13 to a piece of text merely requires examining its alphabetic characters and replacing each one by the letter 13 places further al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Algorithms
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. More advanced algorithms can perform automated deductions (referred to as automated reasoning) and use mathematical and logical tests to divert the code execution through various routes (referred to as automated decision-making). Using human characteristics as descriptors of machines in metaphorical ways was already practiced by Alan Turing with terms such as "memory", "search" and "stimulus". In contrast, a Heuristic (computer science), heuristic is an approach to problem solving that may not be fully specified or may not guarantee correct or optimal results, especially in problem domains where there is no well-defined correct or optimal result. As an effective method, an algorithm ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography Law
Cryptography is the practice and study of encrypting information, or in other words, securing information from unauthorized access. There are many different cryptography laws in different nations. Some countries prohibit export of cryptography software and/or encryption algorithms or cryptoanalysis methods. Some countries require decryption keys to be recoverable in case of a police investigation. Overview Issues regarding cryptography law fall into four categories: * Export control, which is the restriction on export of cryptography methods within a country to other countries or commercial entities. There are international export control agreements, the main one being the Wassenaar Arrangement. The Wassenaar Arrangement was created after the dissolution of COCOM (Coordinating committee for Multilateral Export Controls), which in 1989 "decontrolled password and authentication-only cryptography." * Import controls, which is the restriction on using certain types of cryptography ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
