Computerphile - 2023-05-03
An oldie but a goodie, Dr Mike Pound revisits the Log-Jam attack. Original Log Jam paper: https://bit.ly/C_LogJamPaper Thanks to David Domminney Fowler for his help with the woeful framerate of the second camera footage. https://www.facebook.com/computerphile https://twitter.com/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
Nothing like a new Mike Computerphile video :D
Even in 2.5 FPS!
Yes the FPS were kind of creepy....
…talking about cryptography ❤
Yeah...I got interested in cryptography because of this guy
Didn't know Mike had changed his last name, that's some serious dedication!
2.5fps with that smooth transition is absolutely trippy and satisfactory. Especially when writting, the text just pops up into existence randomly, amazing
Funnily enough I was maxing my CPU at 100% compiling software inside docker containers and I thought I had glitched something, even though my browser was "niced". I niced the container and pressed back to watch it again, it was funny.
@@monad_tcp Haha
Actually I was starting to think this was AI generated :P
For me it kinda looks like writing in cheap animations, where the hand just slides in the writing direction, bobbing up and down a little randomly and the text just appears behind it.
Magic marker :)
FPS comments, for people like me who can't read quite that quickly (I think this is all of them):
oops, 2.5 fps - sorry!
strong cct vibes
frame-rate mismatches are painful huh
maybe you're wondering how this happened?
because 2.5fps is rather an unusual framerate
this camera was used for a different piece of work
sean (the fool) forgot to check the settings
normally this camera (a canon xa50)
stays in the bag for computerphile shoots
but, having used it to timelapse something
it was set to 4k 25fps but on a 10x settings
maybe an ai frame interpolator can help...
or make mike look like 'the flash'
better, or worse? i kinda like it...
Thanks for this :) -Sean
Lol I saw the first one, but didn't even notice I was missing any others
Reminds me times when as a teenager I attempted to load the latest games on an outdated PC. Humbling experience ;)
Thank you for this! I now just need to block out the bottom half of my screen, so they do not distract me anymore. -- Edit: @Computerphile I don't mind reading the explanation, but please, not like this. The short, almost subliminal-like messages making your 2.5 FPS excuses at the bottom of the screen were very distracting from the lecture itself. Had to constantly pause/rewind. Basically, I forced myself to watch a sup bar video twice.
Somehow, I kind of like the 2.5fps, but maybe the explanation is better at the very end.
The idea of pre-computing a large part of the decryption for each prime number is similar to how GSM and later mobile phone encryption systems were broken - we called the pre-computed data ‘Rainbow Tables’
Rainbow tables exist in a lot of contexts and are quite an old concept.
The tables containing precomputed hashes (for password cracking) are also referred to as Rainbow tables.
@@iammeok yes, they are often called that way, but the term is misused in that case imo. Those are simply hash tables, while rainbow tables use a mechanism of chaining reduction functions, as described in Oechslin‘s paper from 2003.
The real problem with mobile phone encryption (at least back in the GSM days) was that it was made deliberately weak due to pressure from spy agencies.
The man in the middle managed to corrupt the paper and pen scenes 😂
7:03 due to the accidental low framerate, it looks like Mike writes "mod" by drawing a straight line
Fry: Not sure if B-roll footage is 2.5fps, or…
…my heart is just THAT excited to see another Dr. Poundtown cryptography/attack video on Computerphile.
Glad i want the only one seeing that.
It says so on the video
@@santiagog YouTube mobile makes it really dumb to read the descriptions beyond about 4 words.
@@AndrewFrink It's literally on screen 1:00
Some footage is being downgraded to 2.5 FPS by a malicious actor ;)
13:37 Mike... Stop. Promising. Videos. you are a computerphile hydra at this point 😂
Hydra... 🤔🤔 They should do a video on hydra as well if they haven't
"And it has a generator of 2" Such an unremarkable number for such a remarkable prime
It's not a property of the prime number itself. The key exchange requires the choice of two separate, publically-disclosable numbers: the giant prime that was mentioned, and a generator, which is allowed to be small
i was expecting him to add the whole "floor" or something since he put pi in the prime generation and that definitely can't be a whole number.
"Such an unremarkable number" 2 is the MOST interesting number out there. wdym?
How is it a prime if it's times by/added to pi in there? isn't pi transcendental?
@@isaaccunningham2042 probably floor to remove the decimal part
3:26 You wasted a golden opportunity for "It's an older code, sir, but it checks out."
The 2.5fps subtitles could have referenced a møøse
A møøse once bit my sister...
If you're wondering how pi was used to get a prime, there should be rounding down (floor) brackets in there. From RFC 2409:
"The prime is 2^1024 - 2^960 - 1 + 2^64 * { [2^894 pi] + 129093 }.
Its hexadecimal value is
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED
EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE65381
FFFFFFFF FFFFFFFF"
Thank you, I was wondering how a transcendental number could possibly be part of a prime.
What calculation was used to prove that it is a prime number?
how do we know [ ] means round to the nearest and not round downwards? This could introduce an off by one error.
@@charlieangkor8649 Square brackets only mean round down. I've edited my comment to clear that up.
@@threeMetreJim RFCs are technical documents used for things like internet protocol definitions. I'd start by looking at RFC 2409. If not, I believe there's at least one method to verify whether a number is prime. They shouldn't be hard to find.
4:03 "the p looks a bit small"
heard that one before
Well now we need a video on how number field sieve works!
I remember being tasked at the time with building a group policy for our windows servers to remove compromised cipher suites as available options. Its cool to finally understand what was really going on with that, since at the time all I understood was there was a downgrade attack that was possible.
I could listen to Mike all day 🎉🎉
Outstanding vid, it's great that people can get such an approachable insight into not only what goes on behind the scenes of something they do every day, but the to and fro of the conflict that is being carried out to break (and keep safe) their communications.
Mike's explanations are just the best everytime
Love Computerphile videos. Keep up the good work.
This is absolute gold. Many thanks Dr. Mike😊
You know it's a good day when Mike uploads a video
Computerphile is amazing! I'm so grateful for new vids 😍
Absolutely loved this, great to hear you speak about this subject
Thanks for the very clear presentation.
Spot on and thoroughly entertaining - Thanks for putting this together!
appreciate the unexpected bonus content about FPS issues :)
The Canon subplot was fun
These guys are freaking awesome!
Love this video and how it's explained even with the technical issues it was still really interesting and engaging
Mike, the hero of explaination.
Fascinating! Thank you for this good story, nicely explained as always 👍
Love the step that's just called "Linear Algebra"
14:48 well that looked pretty magical! I wish I could write at 2 fps 😊
I Remember this my university’s research team worked on this attack!
Geez that slow FPS made me replay those sections. Thanks for the comments, I was ready to diagnose my network.
Would love to see some videos around optimization, specifically LP/ MILP solvers, branch and bound, feasibility pump, etc.
With the 2.5fps storyline going on, this was like 2 videos in one!
I love this guy!
Mike delivered as always.
Very interesting and meaningful video. Good to know the Internet moved away from this potentially insecure versions. Thank you!
These always baffle me at least a bit, but I enjoy watching them all.
NSA: Sorry Timmy. It's more important that we use that money to read your parent's emails rather than give you food and healthcare.
Mike’s taught me more than all my professors combined
Log Jammin is a highly underrated film by Jackie Treehorn
The big lebowski, I understood that reference!
The man in the middle turned out be an expert. Would someone please flush my brain?
Imagine how pucker-inducing dropping a paper like this is for security professionals. 😄
There is nothing more devious than the malicious purple pen.
Finally Dr Mike Pound! Love the guy :)
Is there a video on how these videos are edited and made? This is a really clear way to convey a topic..
A safe prime in RFC is "probably" broken.. and now elliptic curve is used, but, as far as I remember some defaults for elliptic curve are part of RFC and it was mentioned in an older Numberphile video that elliptic curve might be broken too..
This video have amaizing "dreamy" vibe in it.
@CatzHoek - 2023-05-03
That's some serious powerpoint at the paper drawing scenes.
@rhoharane - 2023-05-03
I enjoyed the little side-plot at the bottom
@tadnir50 - 2023-05-04
@@rhoharane 2:59
@tadnir50 - 2023-05-04
@@rhoharane 6:04