LogJam Attack - Computerphile

Рет қаралды 180,139

Күн бұрын

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: 298

@youngfrigo Жыл бұрын

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!

@CatzHoek Жыл бұрын

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

@Mefodii Жыл бұрын

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 8 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 8 ай бұрын

Magic marker :)

@Richardincancale Жыл бұрын

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.

@OhhCrapGuy Жыл бұрын

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.

@qzbnyv Жыл бұрын

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 KZfaq 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 ;)

@luketurner314 Жыл бұрын

7:03 due to the accidental low framerate, it looks like Mike writes "mod" by drawing a straight line

@beyondcatastrophe_ Жыл бұрын

"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

@kubilaykara3167 Жыл бұрын

The man in the middle managed to corrupt the paper and pen scenes 😂

@pearceburns2787 Жыл бұрын

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

@jaredwilliams8621 Жыл бұрын

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.

@spazda_mx5 Жыл бұрын

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.

@LuminaryAluminum Жыл бұрын

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 Жыл бұрын

A møøse once bit my sister...

@FunctionGermany Жыл бұрын

4:03 "the p looks a bit small" heard that one before

@amorphant Жыл бұрын

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.

@mcmillanator Жыл бұрын

Love Computerphile videos. Keep up the good work.

@user-ll4cj2gl2v Жыл бұрын

I could listen to Mike all day 🎉🎉

@QuantumHistorian Жыл бұрын

Well now we need a video on how number field sieve works!

@zwanz0r Жыл бұрын

Computerphile is amazing! I'm so grateful for new vids 😍

@Syntax753 Жыл бұрын

Spot on and thoroughly entertaining - Thanks for putting this together!

@chaitanyabisht Жыл бұрын

You know it's a good day when Mike uploads a video

@napukapu Жыл бұрын

Mike's explanations are just the best everytime

@utkarshmishra1928 Жыл бұрын

This is absolute gold. Many thanks Dr. Mike😊

@MrPhenomenomTV Жыл бұрын

Absolutely loved this, great to hear you speak about this subject

@blizzy78 Жыл бұрын

appreciate the unexpected bonus content about FPS issues :)

@lolzhunter Жыл бұрын

Love this video and how it's explained even with the technical issues it was still really interesting and engaging

@olivier2553 Жыл бұрын

Thanks for the very clear presentation.

@_mathtutor3334 Жыл бұрын

These guys are freaking awesome!

@tim_tmn Жыл бұрын

Mike, the hero of explaination.

@julienwickramatunga7338 Жыл бұрын

Fascinating! Thank you for this good story, nicely explained as always 👍

@eliana993 Жыл бұрын

I Remember this my university’s research team worked on this attack!

@elektrikblu7331 Жыл бұрын

Love the step that's just called "Linear Algebra"

@droppedpasta Жыл бұрын

The Canon subplot was fun

@garbox101 Жыл бұрын

Geez that slow FPS made me replay those sections. Thanks for the comments, I was ready to diagnose my network.

@unvergebeneid Жыл бұрын

14:48 well that looked pretty magical! I wish I could write at 2 fps 😊

@tommydowning3481 Жыл бұрын

I love this channel. Fascinating stuff.

@__3Li__ Жыл бұрын

Would love to see some videos around optimization, specifically LP/ MILP solvers, branch and bound, feasibility pump, etc.

@hugofriberg3445 Жыл бұрын

Mike’s taught me more than all my professors combined

@Kyuubi840 Жыл бұрын

Very interesting and meaningful video. Good to know the Internet moved away from this potentially insecure versions. Thank you!

@get953 Жыл бұрын

These always baffle me at least a bit, but I enjoy watching them all.

@DEADLYPiXELEGaming Жыл бұрын

There is nothing more devious than the malicious purple pen.

@Tospaa Жыл бұрын

Finally Dr Mike Pound! Love the guy :)

@vladimirpain3942 Жыл бұрын

This video have amaizing "dreamy" vibe in it.

@test4274 Жыл бұрын

I love this guy!

@lukor-tech Жыл бұрын

Mike delivered as always.

@Hacktheplanet_ Жыл бұрын

I see the poundmiester, im watching it

@x_tye_x 2 ай бұрын

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

@AlperYilmaz1 Жыл бұрын

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..

@martixy2 Жыл бұрын

Imagine how pucker-inducing dropping a paper like this is for security professionals. 😄

@Guido.Fawkes.1 Жыл бұрын

Log Jammin is a highly underrated film by Jackie Treehorn

@iammeok Жыл бұрын

The big lebowski, I understood that reference!

@wchen2340 6 ай бұрын

The man in the middle turned out be an expert. Would someone please flush my brain?

@synchro-dentally1965 Жыл бұрын

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.

@chaitanyakolluru2256 Жыл бұрын

Is there a video on how these videos are edited and made? This is a really clear way to convey a topic..

@ofskittlez Жыл бұрын

Does this fall under the category of the law of unintended consequences, regarding the original decision to limit exporting of powerful encryption?

@jonnyawright Жыл бұрын

The 🐐 Dr. Mike Pound

@jimiwills Жыл бұрын

Brilliant 😊

@General12th Жыл бұрын

Hi Dr. Pound! Hi Sean!

@poorusher 5 ай бұрын

Amazing

@theilige Жыл бұрын

whats the difference between preprepared sequences and rainbow tables?

@cmelonwheels 11 ай бұрын

With the 2.5fps storyline going on, this was like 2 videos in one!

@bluegizmo1983 Жыл бұрын

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

@DarioVolaric Жыл бұрын

Never thought Computerphile would be talking about Logjammin' :D

@FalcoGer Жыл бұрын

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.

@adamdude Жыл бұрын

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.

@TS6815 Жыл бұрын

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.

@salvador1683 Жыл бұрын

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?

@leana8959 Жыл бұрын

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 :)

@tr48092 Жыл бұрын

What would it take to break the 2048 bit DHE in 90 seconds?

@gameteindifference2350 Жыл бұрын

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.

@wChris_ Жыл бұрын

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.

@gameeverything816 Жыл бұрын

Neat. And terrifying

@mr.greengold8236 Жыл бұрын

Please make a video on ring signatures and RingCT.

@htho7438 Жыл бұрын

I wonder how Bot Nets compare to the clusters mentioned here. Can someone use them as efficient?

@user-eq2ug7in7b Жыл бұрын

@4:04 "They just noticed the P looks a bit small. Eh" - story of my life

@dufflepod Жыл бұрын

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] ?

@autohmae Жыл бұрын

Man I feel nostalgic now 🙂

@metalcake2288 Жыл бұрын

Computerphile is ahead of the elliptic curve

@gdclemo Жыл бұрын

Please make a video about lattice-based cryptography...

@divitu Жыл бұрын

Weird that the RFC specifies the base in a 1-digit number. Not necessary as far as I'm aware.

@DimonStahlmann Жыл бұрын

4:03 I like this phrase taken out of the context😂

@ejonesss Жыл бұрын

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.

@AndrewFrink Жыл бұрын

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

@Amonimus Жыл бұрын

Not the malicious purple pen!

@scaredyfish Жыл бұрын

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.

@mushroomcrepes4780 Жыл бұрын

good thing 99% of people can't see over 2.5 fps

@SizarieldoR Жыл бұрын

You missed the opportunity to make "Log jammin'" jokes

@lobsterjass Жыл бұрын

I also knew Mike was a super hero. Never knew he was The Flash!

@paultapping9510 10 ай бұрын

So what you're saying is that Uplink was actually quite accurate!

@s1l3nttt Жыл бұрын

hahaah I had just seen that interview a week ago, how lucky

@1992jamo Жыл бұрын

5:16 hurt my brain with that artifact.

@mAssbagflyer Жыл бұрын

Can you talk about how elliptic curve df could be vulnerable? I don't trust the nsa choosinf a curve and all that

@MrSonny6155 Жыл бұрын

Guys, CCTV POV is an artistic choice.

@kmturley1 Жыл бұрын

Ah young Diffy Hellman lad, always getting into a spot of bother. His parents were quite mad!

@Barnaclebeard Жыл бұрын

Did you recreate the over the shoulder shot through perspective projection?!

@AlessandroCattabiani Жыл бұрын

I wonder what would be the memory requirement for the results of the 3 stages of the 1024 prime...

@BIGDAWGSUZZY42069 Жыл бұрын

Sweet

@zxuiji Жыл бұрын

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.