How Secure Shell Works (SSH) - Computerphile

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Published 2019-01-31

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): • SHA: Secure Hashing Algorithm - Compu...

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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)

@nicholas_scott 5 years ago

I remember back in 97, the university officially ended all support for non encrypted remote access, and we were all required to use SSH. Which worked fine. It also made for an excellent tunnelling tool when the same university tried blocking all access to P2P networks.
@El_Grincho 5 years ago

Can't imagine life without SSH.
@dansmoothback9644 5 years ago

Discovering SSH was a game changer for me after i started playing with linux. I discovered SSH forwarding and it blew my goddamn mind. It's been a life saver in a lot of situations and I'll never forget the professor that showed me how to use it.
@clearmenser 5 years ago

Please don't blur for security. It's still readable. Use solid colored bars, for the love of Turing.
@ClarkPotter 3 years ago

Fantastic. You're the professor that true geeks want. You exhibit an approachable charm beneath the geekspeak that invites questions and deep exploration into topics.
@C4CONFIDENCE 2 days ago

Just started exploring the world of SSH. I am coming back to this video with reviews on the learning and practice process.
@oafpolitics179 4 years ago

Thing I love about this video is the listing paper. I bet Nottingham still have boxes and boxes of that stuff floating around from the 80s.
@mh972 4 years ago

SSH tunnels let me watch this video at work without "them" knowing...
@sharkbytefpv4326 5 years ago

Would love to see a video about MOSH from you guys! Thanks, appreciate your work
@mugglepower 8 months ago

the casual focus fade in/out makes it looks like an office episode and its just priceless/.
@Jeremy-su3xy 5 years ago

Nice tutorial. Thanks. Would talk more about the key exchange and establishing process you omitted for the purpose of this video at around 4:00?
@BlueyMcPhluey 5 years ago

perfect timing, I'm taking a networking course right now and they do a terrible job of explaining SSH
@ZedaZ80 5 years ago

Thanks for the subtitles! The auto-generated ones can be pretty inconsistent.
@gwgux 3 years ago

Kudos for taking it down to the packet level! Many videos don't do this!
@paulsander5433 5 years ago

Have you considered doing an episode about BEEP (or BXXP)? This is a standard stream multiplexing protocol as described in RFC's 3080 and 308.
@gabbysmith7579 3 years ago

This was really helpful for me to better understand how it works and why we use it thanks.
@xokocodo 4 years ago

Small detail, but I don't think padding is there to increase the security of the encryption. It's generally just added so that the data matches the block size of the encryption algorithm.
@antoniodellaporta3433 5 years ago

I think there's an error when talking about the packet format. The SSH2's specifications (RFC4253, section 6.3) states as follow: "When encryption is in effect, the packet length, padding length, payload, and padding fields of each packet MUST be encrypted with the given algorithm.". So the packet is all encrypted except the MAC field. Anyway great job as always with bringing such contents, thank you!
@SandmanGeek 3 years ago

SSH is the way to go ... Nicely explained Doc.
@paojek4806 1 year ago

I am using this tunnel, 24/7 in my PC and smartphone for over 3 years now. And I am happy