Computer

Just what was it that took Facebook, Instagram & WhatsApp offline on 4th October 2021? – Dr Steve Bagley investigates! previously titled “Facebook’s Day Off” Facebook announcement on the outage: https://bit.ly/C_FB-Outage The visualisation software Steve was using was BGP play, downloaded from the RIPE website. https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited
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Voting is centuries old, why can’t we move with the times and use our phones, tablets and computers? Tom Scott lays out why e-voting is such a bad idea. More from Tom Scott: http://www.youtube.com/user/enyay and https://twitter.com/tomscott http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of
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This Primer is to accompany the ‘Busy Beaver Turing Machines’ film which can be viewed here: http://youtu.be/CE8UhcyJS0I Professor Brailsford’s code and further reading: http://bit.ly/busybeaver Turing and the Halting Problem: http://youtu.be/macM_MtS_w4 Busy Beaver Turing Machines: http://youtu.be/CE8UhcyJS0I Domino Addition – Numberphile: http://youtu.be/lNuPy-r1GuQ Ackermann Follow Up: http://youtu.be/uNACwX-O5lk ‘Turing Machines Collection’ Playlist: http://www.youtube.com/playlist?list=PLzH6n4zXuckrEzV0CB1xXbSdsP_a7VUoK “The Most Difficult Program to Compute?”
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Cracking the code was only half the battle. To keep the upper hand, when using Bill Tutte’s statistical methods, the detailed counting had to be automated – enter Colossus! Professor Brailsford takes up the story. The professor’s notes: http://www.eprg.org/computerphile/lorenz-combined.pdf Bletchley Park Playlist: https://www.youtube.com/playlist?list=PLzH6n4zXuckrSWWIDJ_3To7ro5-naSk8v Professor Brailsford used the book “Colossus” by B. Jack Copeland and others
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10% off at Squarespace: http://squarespace.com/computerphile Secret services want to read people’s communications, politicians talk about terrorists, but what’s the reality of banning encryption? Ross Anderson, Professor of Security Engineering at the Computer Laboratory, University of Cambridge explains how history repeats itself. The Dress: https://youtu.be/Tw0PlGpaqy4 The VR Cave: https://youtu.be/STMcWUtQr1Y Public Key Cryptography: https://youtu.be/GSIDS_lvRv4 Alan Turing and
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Email is part of the daily routine for many people, but how does a computer deal with email messages? Professor Tom Rodden explains how email is processed so quickly. http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project
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Harry’s: http://www.harrys.com/ use coupon code “COMPUTERPHILE” for $5 off What’s a colourspace and why do we have different ones? It’s horses for courses as Image Analyst Mike Pound explains. Digital Images: https://www.youtube.com/playlist?list=PLzH6n4zXuckpbNdFO2WW78evpMBqgqyp8 Atari ST: Pushing the Limits: https://youtu.be/3OdtfsXOkEY Professor Steve Furber on ARM: COMING SOON! Universe of Triangles: https://www.youtube.com/playlist?list=PLzH6n4zXuckrPkEUK5iMQrQyvj9Z6WCrm http://www.facebook.com/computerphile Tweets by computer_phile This video
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Our eyes can spot edges with no problems, but how do computers determine what’s an edge and what’s not? Image Analyst Dr Mike Pound explains the Sobel Edge detector. How Blurs & Filters work: https://youtu.be/C_zFhWdM4ic The Problem with JPEG: https://youtu.be/yBX8GFqt6GA Secrets Hidden in Images (Steganography): https://youtu.be/TWEXCYQKyDc Man in the Middle Attacks: https://youtu.be/-enHfpHMBo4 Mike’s Code in
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Digital currency, how does it work, what’s a data miner and will Bitcoin last? We asked Professor Ross Anderson of the University of Cambridge Computer Laboratory. The Problem with BitCoin: https://youtu.be/s2XHyzPA9Zc Chip & PIN Fraud: https://youtu.be/Ks0SOn8hjG8 $5 Computer – Raspberry Pi Zero: https://youtu.be/WR0ghM3U0M4 Why Computers Use Binary: https://youtu.be/thrx3SBEpL8 Public Key Cryptography: https://youtu.be/GSIDS_lvRv4 http://www.facebook.com/computerphile Tweets by
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Diffie Hellman has a flaw. Dr Mike Pound explains how a man in the middle could be a big problem, unless we factor it in… Public Key Cryptography: https://youtu.be/GSIDS_lvRv4 Elliptic Curve Cryptography: Coming Soon! https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer
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Postscript took off like a rocket but PDF took its time, many people wondering “What’s it for?” Professor Brailsford’s experience with one such person – a US immigration officer… Unrolling the Loops (Postscript/PDF intro): https://youtu.be/guXgBe2wvEA Fire Pong in Detail: https://youtu.be/ZoZMMg1r_Oc Deep Dream: https://youtu.be/BsSmBPmPeYQ FPS & Digital Video: https://youtu.be/yniSnYtkrwQ Password Cracking: https://youtu.be/7U-RbOKanYs http://www.facebook.com/computerphile Tweets by computer_phile
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Just what is a pipeline in the computer science sense? We asked Computer Science guru Professor Brian Kernighan Why Asimov’s Laws of Robotics Don’t Work: https://youtu.be/7PKx3kS7f4A Brian Kerninghan on Bell Labs: https://youtu.be/QFK6RG47bww Don Knuth on Email: https://youtu.be/QS8qwMna8_o Computer That Changed Everything: https://youtu.be/6LYRgrqJgDc http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley.
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One of the most elegant solutions for cryptography. Dr Mike Pound explains one of his most favourite ciphers. https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran’s Numberphile. More at http://www.bradyharan.com
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Why encrypted group messaging isn’t as secure as point to point. Dr Mike Pound explains this ongoing problem. Instant Messaging & the Signal Protocol: https://youtu.be/DXv1boalsDI Double Ratchet Messaging Encryption: https://youtu.be/9sO2qdTci-s Relevant paper: https://eprint.iacr.org/2017/666.pdf https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile
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Negative Binary Numbers – you may have heard of ‘signed’ numbers, but do you know how they work? Professor Brailsford explains not just how, but why we use the systems we do. Binary Addition: http://youtu.be/WN8i5cwjkSE Most Difficult Program to Compute?: http://youtu.be/i7sm9dzFtEI Floating Point Numbers: http://youtu.be/PZRI1IfStY0 http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited
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Colossus was one of the very first electronic, special purpose, computers and it was created almost two years earlier than the better known ENIAC. We visit Bletchley Park, home of the code breakers, and TNMoC, The National Museum of Computing. Professor Brailsford shows us the Colossus replica. The Most Difficult Program to Compute?: https://youtu.be/i7sm9dzFtEI Computer
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Commonly used grep was written overnight, but why and how did it get its name? Professor Brian Kernighan explains. EXTRA BITS: https://youtu.be/bSaBe6WiC2s Inside an ALT Coin Mining Operation: COMING SOON Unix Pipeline: https://youtu.be/bKzonnwoR2I https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile
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Hitler’s High Command didn’t use Enigma, they used a faster system called Lorenz, but when Allied forces first encountered it, they had no idea what it was and code-named it ‘Tunny’ (Tuna). Professor Brailsford explains why this relates to the early days of Computer Science Next Video in this series: https://youtu.be/yxx3Bkmv3ck The Professor’s Notes: Undulator
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Image filters make most people think of Instagram or Camera Phone apps, but what’s really going on at pixel level? Image Analyst Dr Mike Pound explains some of the most common filters. Secrets Hidden in Images (Steganography): https://youtu.be/TWEXCYQKyDc JPEG ‘files’ & Colour: https://youtu.be/n_uNPbdenRs The Dress: https://youtu.be/Tw0PlGpaqy4 The VR Cave: https://youtu.be/STMcWUtQr1Y JPEG Discrete Cosine Transform (DCT):
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JPEG Isn’t a file format. Image Analyst Mike Pound explains why not in our first in a series about how JPEG works. Colourspaces: https://youtu.be/LFXN9PiOGtY Elegant Compression (The LZ Method): https://youtu.be/goOa3DGezUA Capturing Digital Images (The Bayer Filter): https://youtu.be/LWxu4rkZBLw Discrete Cosine Transform: https://youtu.be/Q2aEzeMDHMA http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer
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Machine Learning where you put in a fraction of the effort? What’s not to like? – Dr Michel Valstar explains Active & Cooperative Learning. https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran’s Numberphile. More
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Secure Hashing Algorithm (SHA1) explained. Dr Mike Pound explains how files are used to generate seemingly random hash strings. EXTRA BITS: https://youtu.be/f8ZP_1K2Y-U Tom Scott on Hash Algorithms: https://youtu.be/b4b8ktEV4Bg http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project to
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Before laser-printers, high quality print-outs were the domain of typesetters, expensive and tightly controlled. In 1979 a Bell Labs team reverse engineered one in their summer vacation. Professor Brailsford has the details. EXTRA BITS – More on Printing and Typesetting History: https://www.youtube.com/watch?v=HdModNEK_1U Mainframes and the Unix Revolution: http://youtu.be/-rPPqm44xLs To find out how the 1980 Bell
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Should Apple unlock a terrorists iPhone for the FBI? Professor Ross Anderson explains how this is a “Pandora’s Box” situation. Buffer Overflow Attacks: https://youtu.be/1S0aBV-Waeo $5 Computer: https://youtu.be/WR0ghM3U0M4 AI Safety: https://youtu.be/IB1OvoCNnWY EXTRA BITS: https://youtu.be/6iGxNku7ilw http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile
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When a Bitcoin Miner Mines, what is happening? Dr Mike Pound exposes the process.. note: at 3:39 Mike mentions a Bitcoin is mined every ten minutes when it is actually a block that is mined every ten minutes, at time of recording a successful block generates 12.5 new Bitcoins. Password Cracking: https://youtu.be/7U-RbOKanYs Onion Routing (TOR):
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The story of recursion continues as Professor Brailsford explains one of the most difficult programs to compute: Ackermann’s function. Professor Brailsford’s programs: http://bit.ly/1nhKtW4 Follow Up Film from the Prof in response to this film: https://www.youtube.com/watch?v=uNACwX-O5lk What on Earth is Recursion?: http://youtu.be/Mv9NEXX1VHc Fibonacci Programming: http://youtu.be/7t_pTlH9HwA Heartbleed, Running the Code: http://youtu.be/1dOCHwf8zVQ VR Series: COMING SOON! Please note,
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The back door that may not be a back door… The suspicion about Dual_EC_DRBG – The Dual Elliptic Curve Deterministic Random Bit Generator – with Dr Mike Pound. EXTRA BITS: https://youtu.be/XEmoD06_mZ0 Nothing up my sleeve Numbers: https://youtu.be/oJWwaQm-Exs Elliptic Curves: https://youtu.be/NF1pwjL9-DE https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science
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Just what is functional programming? We asked a member of the team that created Haskell: John Hughes, Professor of Computer Science at Chalmers University of Technology in Gothenburg. http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project to
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Cookies are controversial and new laws governing them have been introduced in Europe. Extra footage: http://youtu.be/_d0G6FZ_kR4 Featuring Tom Rodden from the University of Nottingham’s Department of Computer Science. http://bit.ly/nottscomputer Follow Computerphile… http://www.facebook.com/computerphile Tweets by computer_phile Video by Sean Riley. Computerphile is a sister project to Brady Haran’s Numberphile. See the full list of Brady’s video
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How do digital cameras turn light into the data that computers can handle? In this second part of our computer vision series, Image Analyst Mike Pound explains the Bayer Filter. Professor Steve Furber on the BBC Micro: https://youtu.be/y4WG549i3YY 2D Images: http://youtu.be/06OHflWNCOE Universe of Triangles: http://youtu.be/KdyvizaygyY?list=PLzH6n4zXuckrPkEUK5iMQrQyvj9Z6WCrm Pushing the Atari Limits: http://youtu.be/3OdtfsXOkEY http://www.facebook.com/computerphile Tweets by computer_phile This
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Correction : as oodles of commenters have pointed out, the clock face should go from 0 to n-1. Also, worth reminding people that Mike has simplified the notation in this video (as he mentions). Mike explains the mathematics behind one of the most important pieces of computer security. (Simplified version with colour mixing analogy linked
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Making yourself the all-powerful “Root” super-user on a computer using a buffer overflow attack. Assistant Professor Dr Mike Pound details how it’s done. The Stack: https://youtu.be/7ha78yWRDlE Botnets: https://youtu.be/UVFmC178_Vs The Golden Key: iPhone Encryption: https://youtu.be/6RNKtwAGvqc 3D Stereo Vision: https://youtu.be/O7B2vCsTpC0 Brain Scanner: https://youtu.be/TQ0sL1ZGnQ4 http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer
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Spies used to meet in the park to exchange code words, now things have moved on – Robert Miles explains the principle of Public/Private Key Cryptography note1: Yes, it should have been ‘Obi Wan’ not ‘Obi One’ 🙂 note2: The string of ‘garbage’ text in the two examples should have been different to illustrate more
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Audible free book: http://www.audible.com/computerphile DoS or Denial of Service Attacks are one thing, but Amplified Denial of Service Attacks could threaten the internet itself. Tom Scott explains what they are. More from Tom Scott: http://www.youtube.com/user/enyay and https://twitter.com/tomscott http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computerphile is a sister project
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Connecting via SSH to a remote machine is second nature to some, but how does it work? Dr Steve Bagley. Dr Mike Pound on Hashing (mentions padding but full video on padding is planned to follow): https://youtu.be/DMtFhACPnTY https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University
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How do websites marry up to their IP addresses? Dr Mike Pound explains the Domain Name System – DNS. https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran’s Numberphile. More at http://www.bradyharan.com
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What goes on TOR stays on TOR, or so we hope. Dr Mike Pound takes us through how Onion Routing works. EXTRA BITS: https://youtu.be/6eWkdyRNfqY End to End Encryption: https://youtu.be/jkV1KEJGKRA Deep Web / Dark Web: https://youtu.be/joxQ_XbsPVw http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham:
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Audible Free Book: http://www.audible.com/computerphile Recursion; like something from the film “Inception”. Even Professor Brailsford says it can be hard to get your head around – watch him make it much easier to understand… EXTRA BITS: http://youtu.be/0pncNKHj-Sc Opening up the Original Mac: http://youtu.be/wFJrHuSXnZM http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley.
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Audible free book: http://www.audible.com/computerphile Unicode is changing, adding tons more icons and smilies – But what’s new and why? Tom Scott takes us through the improvements… More from Tom Scott: http://www.youtube.com/user/enyay and https://twitter.com/tomscott Characters, Symbols & the Unicode Miracle: http://youtu.be/MijmeoH9LT4 Floating Point Numbers: http://youtu.be/PZRI1IfStY0 The VR CAVE: http://youtu.be/STMcWUtQr1Y End for Moore’s Law?: http://youtu.be/X8v1BB0UaDs http://www.facebook.com/computerphile Tweets
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The danger of assuming general artificial intelligence will be the same as human intelligence. Rob Miles explains with a simple example: The deadly stamp collector. The Problem with JPEG: https://youtu.be/yBX8GFqt6GA Apple’s $200,000 Computer: https://youtu.be/PccvZRTUhbI Rabbits, Faces & Hyperspaces: https://youtu.be/q6iqI2GIllI Thanks to Nottingham Hackspace for the location. http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and
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Just what are elliptic curves and why use a graph shape in cryptography? Dr Mike Pound explains. Mike’s myriad Diffie-Hellman videos: https://www.youtube.com/playlist?list=PLzH6n4zXuckpoaxDKOOV26yhgoY2S-xYg https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran’s Numberphile. More at http://www.bradyharan.com
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Audible free book: http://www.audible.com/computerphile Catering for a global audience is difficult, Tom takes us through a ‘timezones’ style explanation of the things you need to keep in mind when internationalising your code. This video features Tom Scott – more from him at: http://www.youtube.com/enyay & https://twitter.com/tomscott The Problem with Time & Timezones: http://youtu.be/-5wpm-gesOY Emoji & the
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Audible free book: http://www.audible.com/computerphile Hashing Algorithms are used to ensure file authenticity, but how secure are they and why do they keep changing? Tom Scott hashes it out. More from Tom Scott: http://www.youtube.com/user/enyay and https://twitter.com/tomscott http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Pigeon Sound Effects courtesy of http://www.freesfx.co.uk/ Computerphile
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How do we exchange a secret key in the clear? Spoiler: We don’t – Dr Mike Pound shows us exactly what happens. Mathematics bit: https://youtu.be/Yjrfm_oRO0w Computing Limit: https://youtu.be/jv2H9fp9dT8 https://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to
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Bit flipping a stream cipher could help you hit the Jackpot! But not with HMAC. Dr Mike Pound explains. Correction : “pseudo” is spelled incorrectly on the graphic. http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project to
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