Computer

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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Alan Turing almost accidentally created the blueprint for the modern day digital computer. Here Mark Jago takes us through The Halting Problem. Turing Machines Explained: https://youtu.be/dNRDvLACg5Q Busy Beaver: https://youtu.be/CE8UhcyJS0I VR Simulator: http://youtu.be/Lm0lA0enPSk What on Earth is Recursion?: http://youtu.be/Mv9NEXX1VHc Thanks to Assistant Professor Mark Jago of the University of Nottingham. http://www.facebook.com/computerphile Tweets by computer_phile This video
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End to end encryption, government ministers are again talking about stopping it. What is it and why might that be a bad idea? Dr Mike Pound explains. Hololens: https://youtu.be/gp8UiYOw8Fc Blockchain: https://youtu.be/qcuc3rgwZAE 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
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What does it mean for something to be Turing Complete? Professor Brailsford explains. Turing Machine Primer: https://youtu.be/DILF8usqp7M Turing Machines Explained: https://youtu.be/dNRDvLACg5Q Chomsky Hierarchy: https://youtu.be/224plb3bCog What on Earth is Recursion?: https://youtu.be/Mv9NEXX1VHc 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
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A web app that works out how many seconds ago something happened. How hard can coding that be? Tom Scott explains how time twists and turns like a twisty-turny thing. It’s not to be trifled with! A Universe of Triangles: http://www.youtube.com/watch?v=KdyvizaygyY LZ Compression in Text: http://www.youtube.com/watch?v=goOa3DGezUA Characters, Symbols and the Unicode Miracle: http://www.youtube.com/watch?v=MijmeoH9LT4 More from
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Quick Sort is a popular sorting algorithm, but how does it work? Alex continues our exploration of sorting algorithms with a quick look at quick sort. Original ‘get sorted’ film: http://youtu.be/kgBjXUE_Nwc Cookies: http://youtu.be/LHSSY8QNvew Alex’s code that generated the data for the tests on the original ‘get sorted’ video: https://github.com/apinkney97/Sorts Alex’s graph of all the results
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Audible free book: http://www.audible.com/computerphile JavaScript is dangerous! Why? How are websites vulnerable to it? Find out about bug-bounties from Tom Scott. 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 to Brady Haran’s Numberphile. See the full list of
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For the past year, we’ve been asking this as a sound-check question. Here are the results! Professor Graham Hutton (Haskell) Joseph Best (BBC Basic) David CX (Java / Python) Lorraine Underwood (PHP) Rob Miles (Python) Charles Arthur (Python) Sarah Spencer (Javascript) Matt Denton (C) Matt Lloyd (C/Python/PHP) Ian Dickinson (C) Tom Sheridan (Python) Spencer Owen
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If you don’t secure your web forms, one mistaken click could be all it takes for your users to delete their own accounts. Tom Scott explains. http://www.facebook.com/computerphile Tweets by computer_phile More from Tom Scott: http://www.youtube.com/user/enyay and https://twitter.com/tomscott Hacking Websites with SQL Injection: http://www.youtube.com/watch?v=_jKylhJtPmI Cracking Websites with Cross Site Scripting: http://www.youtube.com/watch?v=L5l9lSnNMxg This video was filmed and
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Security of users’ passwords should be at the forefront of every web developer’s mind. Tom takes us through the insecure ways in which some websites deal with passwords. Note: At circa 8mins, the animation does not show how the ‘salt’ is also stored in the database alongside the username. Hashing Algorithms and Security: http://youtu.be/b4b8ktEV4Bg Security
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Why can’t floating point do money? It’s a brilliant solution for speed of calculations in the computer, but how and why does moving the decimal point (well, in this case binary or radix point) help and how does it get currency so wrong? 3D Graphics Playlist: http://www.youtube.com/playlist?list=PLzH6n4zXuckrPkEUK5iMQrQyvj9Z6WCrm The Trouble with Timezones: http://youtu.be/-5wpm-gesOY More from Tom
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What does a GPU do differently to a CPU and why don’t we use them for everything? First of a series from Jem Davies, VP of Technology at ARM. Floating Point Numbers: http://youtu.be/PZRI1IfStY0 Why Computers Use Binary: https://youtu.be/thrx3SBEpL8 How Bitcoin Works: https://youtu.be/JyxRH18YlpA Triangles & Pixels (Graphics Playlist): https://www.youtube.com/playlist?list=PLzH6n4zXuckrPkEUK5iMQrQyvj9Z6WCrm http://www.facebook.com/computerphile Tweets by computer_phile This video was
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Byte ordering, or boiled egg orientation, endianness is important! Dr Steve Bagley on the computer science topic named after something from an 18th century novel…. The copy of Gulliver’s Travels used in the graphics was found at archive.org and can be viewed here: http://bit.ly/C_Gulliver The animations of the hex to binary have a classic ‘out
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Never use JPEG with text. But why? Image Analyst Mike Pound explains what goes wrong when JPEG tries to compress text. Holy Grail of AI: https://youtu.be/tlS5Y2vm02c Computer That Changed Everything: https://youtu.be/6LYRgrqJgDc Arduino Hardware: https://youtu.be/b4z1zkmo1BE How JPEG Works: https://www.youtube.com/playlist?list=PLzH6n4zXuckoAod3z31QEST1ZaizBuNHh http://www.facebook.com/computerphile Tweets by computer_phile This video was filmed and edited by Sean Riley. Computer Science at the
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