Public Key Cryptography - Computerphile

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Published 2014-07-22
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 clearly that there are two different systems in use.

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This video was filmed and edited by Sean Riley.

Computer Science at the University of Nottingham: bit.ly/nottscomputer

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All Comments (21)
  • Jeez, I wish this is how it was explained to me the first time. This was a brilliant video. And now I appreciate the brilliance of public key encryption. The idea of encrypting something twice, first with the other person's public key so only they can decrypt it, and then sign it with your own private key, so they know that you were legitimately the person sending it, is GENIUS. Thank you very, very much.
  • @BhargaviCN
    Cryptographers are upset because you didn't mention "Alice or Bob or THE EVE!"
  • You explained this better in 6 mins than my lecturer did in a whole semester. Thank you.
  • never ever understood public private key encryption decryption in this way, coming from a non-coding background the epiphany I had at 5:00 was just amazing, great explanation!!
  • @captplatonic
    This was the first explanation in about 5 on public key cryptography where I had my lightbulb moment - thank you!
  • @krazyq00
    It's crazy how after class and so many videos, only one of them finally makes sense (this one) and now when I start watching the other stuff it starts making sense. Every time I search for stuff now I hope I find a video from you guys with an explanation.
  • @Noxbite
    I love listening to that guy. His use of examples and explaining is out of this world. Please more videos! Whatever it might be about
  • @foxdash
    Wow this guy is really good on camera, would be nice to see him in more videos.
  • You made my day.I am a Commerce student who had no idea about Public key and I needed to understand it because of IT subject in my course curriculum. I was totally frustrated and was not able to understand the concept from my book however by watching you video I got a basic idea about Public Key which is more than sufficient for my purpose.Thanks for the video.Love from India.
  • I'd like to see some simple algorithms on how exactly information is encrypted and decrypted with the keys.
  • I just waste my time watching other channels for this kind of stuff when I know in the end this is where the real juice is. Impeccable.
  • @ankontini
    Thank you! Finally a video that explains what public keys are!!
  • @shayansec
    Really he has oversimplified it...no one can simplify it more than him in just 6 minutes. Great man!!
  • @Jacksaur_
    This was the first explanation I've seen that actually explained there was nothing special between the keys other than which one you personally made public or private. I never understood why anything done with your public key could only ever be undone with your private, but yet you could also sign emails with your private key to have them confirmed through the public without risking the private at all. Brilliant video.
  • @jordansean18
    I must have heard dozens of different explanations of public key encryption, but this one is the first one that just makes sense for the big picture of it all!
  • I was trying to get started on cryptography in my spare time and tried to understand the private/public key thing, but now it makes complete sense. Now I have to learn a bazillion more things and probably go to uni for computer science.
  • This is a great explanation. I never understood the concept and it bothered me very much being an IT person. This is an exciting concept and I now understand the value of it.
  • @veloxsouth
    This is the clearest explanation I've ever seen for asymmetric cryptography.
  • @MiscDotGeek
    Where has this video been all my life. Thank you. Excellent explanation, oversimplifications and all. Regarding that, sometimes it takes oversimplifying something so that you can see the elegance of it more clearly. The details will come later.