LogJam Attack - Computerphile
An oldie but a goodie, Dr Mike Pound revisits the Log-Jam attack.
Original Log Jam paper: bit.ly/C_LogJamPaper
Thanks to David Domminney Fowler for his help with the woeful framerate of the second camera footage.
/ computerphile
/ computer_phile
This video was filmed and edited by Sean Riley.
Computer Science at the University of Nottingham: bit.ly/nottscomputer
Computerphile is a sister project to Brady Haran's Numberphile. More at www.bradyharan.com
Пікірлер: 300
That's some serious powerpoint at the paper drawing scenes.
@rhoharane
Жыл бұрын
I enjoyed the little side-plot at the bottom
@tadnir50
Жыл бұрын
@@rhoharane 2:59
@tadnir50
Жыл бұрын
@@rhoharane 6:04
Nothing like a new Mike Computerphile video :D
@dembro27
Жыл бұрын
Even in 2.5 FPS!
@ChrisSmith-lk2vq
Жыл бұрын
Yes the FPS were kind of creepy....
@tiagosouza5650
Жыл бұрын
…talking about cryptography ❤
@chaitanyabisht
Жыл бұрын
Yeah...I got interested in cryptography because of this guy
@Svish_
Жыл бұрын
Didn't know Mike had changed his last name, that's some serious dedication!
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...
@Computerphile
Жыл бұрын
Thanks for this :) -Sean
@esquilax5563
Жыл бұрын
Lol I saw the first one, but didn't even notice I was missing any others
@pavel9652
Жыл бұрын
Reminds me times when as a teenager I attempted to load the latest games on an outdated PC. Humbling experience ;)
@dani33300
Жыл бұрын
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.
@ikjadoon
Жыл бұрын
Somehow, I kind of like the 2.5fps, but maybe the explanation is better at the very end.
2.5fps with that smooth transition is absolutely trippy and satisfactory. Especially when writting, the text just pops up into existence randomly, amazing
@monad_tcp
Жыл бұрын
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.
@akanate4587
Жыл бұрын
@@monad_tcp Haha
@legobit
Жыл бұрын
Actually I was starting to think this was AI generated :P
@Lampe2020
6 ай бұрын
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.
@DavidMartinez-is7gu
6 ай бұрын
Magic marker :)
7:03 due to the accidental low framerate, it looks like Mike writes "mod" by drawing a straight line
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’
@totlyepic
Жыл бұрын
Rainbow tables exist in a lot of contexts and are quite an old concept.
@iammeok
Жыл бұрын
The tables containing precomputed hashes (for password cracking) are also referred to as Rainbow tables.
@7Mango033
Жыл бұрын
@@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.
@jfwfreo
Жыл бұрын
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.
13:37 Mike... Stop. Promising. Videos. you are a computerphile hydra at this point 😂
@AquilaSornoAranion
Жыл бұрын
Hydra... 🤔🤔 They should do a video on hydra as well if they haven't
The man in the middle managed to corrupt the paper and pen scenes 😂
"And it has a generator of 2" Such an unremarkable number for such a remarkable prime
@esquilax5563
Жыл бұрын
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
@platinummyrr
Жыл бұрын
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.
@iammeok
Жыл бұрын
"Such an unremarkable number" 2 is the MOST interesting number out there. wdym?
@isaaccunningham2042
Жыл бұрын
How is it a prime if it's times by/added to pi in there? isn't pi transcendental?
@platinummyrr
Жыл бұрын
@@isaaccunningham2042 probably floor to remove the decimal part
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.
@AndrewFrink
Жыл бұрын
Glad i want the only one seeing that.
@santiagog
Жыл бұрын
It says so on the video
@AndrewFrink
Жыл бұрын
@@santiagog KZread mobile makes it really dumb to read the descriptions beyond about 4 words.
@josephs.7960
Жыл бұрын
@@AndrewFrink It's literally on screen 1:00
@pavel9652
Жыл бұрын
Some footage is being downgraded to 2.5 FPS by a malicious actor ;)
4:03 "the p looks a bit small" heard that one before
3:26 You wasted a golden opportunity for "It's an older code, sir, but it checks out."
@hammondeggsmusic
Жыл бұрын
The 2.5fps subtitles could have referenced a møøse
@JohnDoe-jh5yr
11 ай бұрын
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"
@quinnbattaglia5189
Жыл бұрын
Thank you, I was wondering how a transcendental number could possibly be part of a prime.
@threeMetreJim
Жыл бұрын
What calculation was used to prove that it is a prime number?
@charlieangkor8649
Жыл бұрын
how do we know [ ] means round to the nearest and not round downwards? This could introduce an off by one error.
@amorphant
Жыл бұрын
@@charlieangkor8649 Square brackets only mean round down. I've edited my comment to clear that up.
@amorphant
Жыл бұрын
@@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.
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.
Well now we need a video on how number field sieve works!
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.
I could listen to Mike all day 🎉🎉
The Canon subplot was fun
Mike's explanations are just the best everytime
Love Computerphile videos. Keep up the good work.
I Remember this my university’s research team worked on this attack!
Love the step that's just called "Linear Algebra"
You know it's a good day when Mike uploads a video
appreciate the unexpected bonus content about FPS issues :)
Computerphile is amazing! I'm so grateful for new vids 😍
14:48 well that looked pretty magical! I wish I could write at 2 fps 😊
This is absolute gold. Many thanks Dr. Mike😊
Spot on and thoroughly entertaining - Thanks for putting this together!
Absolutely loved this, great to hear you speak about this subject
Geez that slow FPS made me replay those sections. Thanks for the comments, I was ready to diagnose my network.
Thanks for the very clear presentation.
Love this video and how it's explained even with the technical issues it was still really interesting and engaging
These guys are freaking awesome!
Mike, the hero of explaination.
Fascinating! Thank you for this good story, nicely explained as always 👍
The 2.5 fps writing is weirdly cool. It’s like Mike is a speedster who has to slow down so we can see his work
Would love to see some videos around optimization, specifically LP/ MILP solvers, branch and bound, feasibility pump, etc.
Log Jammin is a highly underrated film by Jackie Treehorn
@iammeok
Жыл бұрын
The big lebowski, I understood that reference!
@wchen2340
4 ай бұрын
The man in the middle turned out be an expert. Would someone please flush my brain?
I see the poundmiester, im watching it
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.
Very interesting and meaningful video. Good to know the Internet moved away from this potentially insecure versions. Thank you!
There is nothing more devious than the malicious purple pen.
Imagine how pucker-inducing dropping a paper like this is for security professionals. 😄
Mike’s taught me more than all my professors combined
Is there a video on how these videos are edited and made? This is a really clear way to convey a topic..
Finally Dr Mike Pound! Love the guy :)
I love this guy!
Mike delivered as always.
These always baffle me at least a bit, but I enjoy watching them all.
With the 2.5fps storyline going on, this was like 2 videos in one!
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..
I'm really curious, what is the font used in the videos of Computerphiles? I think it really defines the style and I really like it :)
Does this fall under the category of the law of unintended consequences, regarding the original decision to limit exporting of powerful encryption?
This video have amaizing "dreamy" vibe in it.
I love this channel. Fascinating stuff.
Seriously... why is there a Pi in the prime for Oakley Group 2? I think even 2Blue1Brown would have sleepless nights tracking down the hidden circle in that little nugget.
@martin.thogersen
Жыл бұрын
The formula doesn't even return an integer. Unless it assumes some finite precision of decimals?
@InappropriatePolarbear
Жыл бұрын
The hard brackets notation around [2^894 * pi] indicates that it should be rounded to the nearest integer.
@martin.thogersen
Жыл бұрын
He uses round brackets in the video, not hard/square.
@charlieangkor8649
Жыл бұрын
This is Computerphile, not Numberphile. They don't know that pi is an irrational number.
@charlieangkor8649
Жыл бұрын
@@InappropriatePolarbear And if it's 1.50 what is the value of [1.50]? And [-1.50] ?
The 🐐 Dr. Mike Pound
Hi Dr. Pound! Hi Sean!
Lol I love the little text explanations in the corner of the video about the atrocious 2.5 FPS issue 😂 make sure to give Sean two and a half smacks, one for each frame per second lmao
2:22 If it hasnt been done already, I think a video about the Crypto Wars would be a really interesting topic to have on computerphile.
Did you recreate the over the shoulder shot through perspective projection?!
Amazing
whats the difference between preprepared sequences and rainbow tables?
Never thought Computerphile would be talking about Logjammin' :D
Brilliant 😊
I have a question. Back in 2015 when they used the 1024 bit security, couldnt they just use the 2000 one? Why go fir the lower?
@4:04 "They just noticed the P looks a bit small. Eh" - story of my life
So what you're saying is that Uplink was actually quite accurate!
good thing 99% of people can't see over 2.5 fps
I wonder if there's been any studies on how many years it would take to break 2000 bit primes compared to processing power capabilities over the next 30 years.
4:03 "they only noticed that the **p** is a bit small" Logjam vulnerable DH handshakes evidently have a lot in common with my high school girlfriends
@threeMetreJim
Жыл бұрын
A bit small, but no worries? Can't work out why anyone would bother to bring that up.
4:03 I like this phrase taken out of the context😂
Weird that the RFC specifies the base in a 1-digit number. Not necessary as far as I'm aware.
You missed the opportunity to make "Log jammin'" jokes
You simply configure the server to not permit weak schemes. open vpn server actually allows to define a dhparam file. I use a 4096 bit one, it contains p and g, were p is the 4096 bit public prime and g is the generator. Just generating the prime took a few dozen minutes.
Neat. And terrifying
These things make me wonder if there are already similar attacks done and most importantly the threat of storing data to decrypt later.
@cameron7374
Жыл бұрын
I remember hearing that there is people (probably governments?) just stockpiling encrypted data in the hopes that they'll be able to use quantum computing to just decrypt all of it a few years from now.
Please make a video on ring signatures and RingCT.
Ah young Diffy Hellman lad, always getting into a spot of bother. His parents were quite mad!
5:16 hurt my brain with that artifact.
with a name like logjam i thought you was talking about either a variant of log4j or overwhelming the server logs making it confusing to a security admin.
Computerphile is ahead of the elliptic curve
Not the malicious purple pen!
Man I feel nostalgic now 🙂
Sweet
Please make a video about lattice-based cryptography...
Is it just me, or is the frame rate of the overhead camera much lower than the main camera?
Sounds like bit encryptions should be upgraded to say 16k bit encryptions for the foreseeable future and then later 128k bit encryptions, sure it sounds a bit ridiculous but on the other hand by the time the encryptions are broken the information would likely be no longer valuable.
What would it take to break the 2048 bit DHE in 90 seconds?
I also knew Mike was a super hero. Never knew he was The Flash!
I wonder how Bot Nets compare to the clusters mentioned here. Can someone use them as efficient?
10:45 blew my mind... it's the same number every time?!
Was the over the shoulder camera footage generated by openai?
So when on Sept 10, 2001 they said they lost 2.3 Trillion dollars, i wonder how many heavy decryption machines were made?
Linux Tech Tips recently got hacked via a session token attack, and I’m wondering why that is still possible, and if there are any ways to address it? I’m thinking maybe something involving the TPM so once a key is generated it’s never readable.
So if we assume nation starts are collecting data right now using 2000bit keys for encryption, given current processing power gains, when would a nation state sized bad actor be able to break these? Can you build dedicated asics to do this even faster than using general purpose hardware?
@monkyyy0
Жыл бұрын
Encryption grows at 2^n 2000 bit encryption wouldnt be broken
hahaah I had just seen that interview a week ago, how lucky
I mean, as a client, i always notice the small P
The frame rate is slow but the image is very sharp, I think is better than the usual
Guys, CCTV POV is an artistic choice.