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

  • @CatzHoek
    @CatzHoek Жыл бұрын

    That's some serious powerpoint at the paper drawing scenes.

  • @rhoharane

    @rhoharane

    Жыл бұрын

    I enjoyed the little side-plot at the bottom

  • @tadnir50

    @tadnir50

    Жыл бұрын

    ​@@rhoharane 2:59

  • @tadnir50

    @tadnir50

    Жыл бұрын

    ​@@rhoharane 6:04

  • @youngfrigo
    @youngfrigo Жыл бұрын

    Nothing like a new Mike Computerphile video :D

  • @dembro27

    @dembro27

    Жыл бұрын

    Even in 2.5 FPS!

  • @ChrisSmith-lk2vq

    @ChrisSmith-lk2vq

    Жыл бұрын

    Yes the FPS were kind of creepy....

  • @tiagosouza5650

    @tiagosouza5650

    Жыл бұрын

    …talking about cryptography ❤

  • @chaitanyabisht

    @chaitanyabisht

    Жыл бұрын

    Yeah...I got interested in cryptography because of this guy

  • @Svish_

    @Svish_

    Жыл бұрын

    Didn't know Mike had changed his last name, that's some serious dedication!

  • @OhhCrapGuy
    @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

    @Computerphile

    Жыл бұрын

    Thanks for this :) -Sean

  • @esquilax5563

    @esquilax5563

    Жыл бұрын

    Lol I saw the first one, but didn't even notice I was missing any others

  • @pavel9652

    @pavel9652

    Жыл бұрын

    Reminds me times when as a teenager I attempted to load the latest games on an outdated PC. Humbling experience ;)

  • @dani33300

    @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

    @ikjadoon

    Жыл бұрын

    Somehow, I kind of like the 2.5fps, but maybe the explanation is better at the very end.

  • @Mefodii
    @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

    @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

    @akanate4587

    Жыл бұрын

    @@monad_tcp Haha

  • @legobit

    @legobit

    Жыл бұрын

    Actually I was starting to think this was AI generated :P

  • @Lampe2020

    @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

    @DavidMartinez-is7gu

    6 ай бұрын

    Magic marker :)

  • @luketurner314
    @luketurner314 Жыл бұрын

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

  • @Richardincancale
    @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

    @totlyepic

    Жыл бұрын

    Rainbow tables exist in a lot of contexts and are quite an old concept.

  • @iammeok

    @iammeok

    Жыл бұрын

    The tables containing precomputed hashes (for password cracking) are also referred to as Rainbow tables.

  • @7Mango033

    @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

    @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.

  • @pearceburns2787
    @pearceburns2787 Жыл бұрын

    13:37 Mike... Stop. Promising. Videos. you are a computerphile hydra at this point 😂

  • @AquilaSornoAranion

    @AquilaSornoAranion

    Жыл бұрын

    Hydra... 🤔🤔 They should do a video on hydra as well if they haven't

  • @kubilaykara3167
    @kubilaykara3167 Жыл бұрын

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

  • @beyondcatastrophe_
    @beyondcatastrophe_ Жыл бұрын

    "And it has a generator of 2" Such an unremarkable number for such a remarkable prime

  • @esquilax5563

    @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

    @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

    @iammeok

    Жыл бұрын

    "Such an unremarkable number" 2 is the MOST interesting number out there. wdym?

  • @isaaccunningham2042

    @isaaccunningham2042

    Жыл бұрын

    How is it a prime if it's times by/added to pi in there? isn't pi transcendental?

  • @platinummyrr

    @platinummyrr

    Жыл бұрын

    @@isaaccunningham2042 probably floor to remove the decimal part

  • @qzbnyv
    @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

    @AndrewFrink

    Жыл бұрын

    Glad i want the only one seeing that.

  • @santiagog

    @santiagog

    Жыл бұрын

    It says so on the video

  • @AndrewFrink

    @AndrewFrink

    Жыл бұрын

    ​@@santiagog KZread mobile makes it really dumb to read the descriptions beyond about 4 words.

  • @josephs.7960

    @josephs.7960

    Жыл бұрын

    @@AndrewFrink It's literally on screen 1:00

  • @pavel9652

    @pavel9652

    Жыл бұрын

    Some footage is being downgraded to 2.5 FPS by a malicious actor ;)

  • @FunctionGermany
    @FunctionGermany Жыл бұрын

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

  • @LuminaryAluminum
    @LuminaryAluminum Жыл бұрын

    3:26 You wasted a golden opportunity for "It's an older code, sir, but it checks out."

  • @hammondeggsmusic

    @hammondeggsmusic

    Жыл бұрын

    The 2.5fps subtitles could have referenced a møøse

  • @JohnDoe-jh5yr

    @JohnDoe-jh5yr

    11 ай бұрын

    ​A møøse once bit my sister...

  • @amorphant
    @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

    @quinnbattaglia5189

    Жыл бұрын

    Thank you, I was wondering how a transcendental number could possibly be part of a prime.

  • @threeMetreJim

    @threeMetreJim

    Жыл бұрын

    What calculation was used to prove that it is a prime number?

  • @charlieangkor8649

    @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

    @amorphant

    Жыл бұрын

    @@charlieangkor8649 Square brackets only mean round down. I've edited my comment to clear that up.

  • @amorphant

    @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.

  • @jaredwilliams8621
    @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.

  • @QuantumHistorian
    @QuantumHistorian Жыл бұрын

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

  • @spazda_mx5
    @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.

  • @user-ll4cj2gl2v
    @user-ll4cj2gl2v Жыл бұрын

    I could listen to Mike all day 🎉🎉

  • @droppedpasta
    @droppedpasta Жыл бұрын

    The Canon subplot was fun

  • @napukapu
    @napukapu Жыл бұрын

    Mike's explanations are just the best everytime

  • @mcmillanator
    @mcmillanator Жыл бұрын

    Love Computerphile videos. Keep up the good work.

  • @eliana993
    @eliana993 Жыл бұрын

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

  • @elektrikblu7331
    @elektrikblu7331 Жыл бұрын

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

  • @chaitanyabisht
    @chaitanyabisht Жыл бұрын

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

  • @blizzy78
    @blizzy78 Жыл бұрын

    appreciate the unexpected bonus content about FPS issues :)

  • @zwanz0r
    @zwanz0r Жыл бұрын

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

  • @unvergebeneid
    @unvergebeneid Жыл бұрын

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

  • @utkarshmishra1928
    @utkarshmishra1928 Жыл бұрын

    This is absolute gold. Many thanks Dr. Mike😊

  • @Syntax753
    @Syntax753 Жыл бұрын

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

  • @MrPhenomenomTV
    @MrPhenomenomTV Жыл бұрын

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

  • @garbox101
    @garbox101 Жыл бұрын

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

  • @olivier2553
    @olivier2553 Жыл бұрын

    Thanks for the very clear presentation.

  • @lolzhunter
    @lolzhunter Жыл бұрын

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

  • @_mathtutor3334
    @_mathtutor3334 Жыл бұрын

    These guys are freaking awesome!

  • @tim_tmn
    @tim_tmn Жыл бұрын

    Mike, the hero of explaination.

  • @julienwickramatunga7338
    @julienwickramatunga7338 Жыл бұрын

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

  • @x_tye_x
    @x_tye_x10 күн 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

  • @__3Li__
    @__3Li__ Жыл бұрын

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

  • @Guido.Fawkes.1
    @Guido.Fawkes.1 Жыл бұрын

    Log Jammin is a highly underrated film by Jackie Treehorn

  • @iammeok

    @iammeok

    Жыл бұрын

    The big lebowski, I understood that reference!

  • @wchen2340

    @wchen2340

    4 ай бұрын

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

  • @Hacktheplanet_
    @Hacktheplanet_ Жыл бұрын

    I see the poundmiester, im watching it

  • @synchro-dentally1965
    @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.

  • @Kyuubi840
    @Kyuubi840 Жыл бұрын

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

  • @DEADLYPiXELEGaming
    @DEADLYPiXELEGaming Жыл бұрын

    There is nothing more devious than the malicious purple pen.

  • @martixy2
    @martixy2 Жыл бұрын

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

  • @hugofriberg3445
    @hugofriberg3445 Жыл бұрын

    Mike’s taught me more than all my professors combined

  • @chaitanyakolluru2256
    @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..

  • @Tospaa
    @Tospaa Жыл бұрын

    Finally Dr Mike Pound! Love the guy :)

  • @test4274
    @test4274 Жыл бұрын

    I love this guy!

  • @lukor-tech
    @lukor-tech Жыл бұрын

    Mike delivered as always.

  • @get953
    @get953 Жыл бұрын

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

  • @liliwheeler2204
    @liliwheeler22049 ай бұрын

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

  • @AlperYilmaz1
    @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..

  • @leana8959
    @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 :)

  • @ofskittlez
    @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?

  • @vladimirpain3942
    @vladimirpain3942 Жыл бұрын

    This video have amaizing "dreamy" vibe in it.

  • @tommydowning3481
    @tommydowning3481 Жыл бұрын

    I love this channel. Fascinating stuff.

  • @dufflepod
    @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

    @martin.thogersen

    Жыл бұрын

    The formula doesn't even return an integer. Unless it assumes some finite precision of decimals?

  • @InappropriatePolarbear

    @InappropriatePolarbear

    Жыл бұрын

    The hard brackets notation around [2^894 * pi] indicates that it should be rounded to the nearest integer.

  • @martin.thogersen

    @martin.thogersen

    Жыл бұрын

    He uses round brackets in the video, not hard/square.

  • @charlieangkor8649

    @charlieangkor8649

    Жыл бұрын

    This is Computerphile, not Numberphile. They don't know that pi is an irrational number.

  • @charlieangkor8649

    @charlieangkor8649

    Жыл бұрын

    @@InappropriatePolarbear And if it's 1.50 what is the value of [1.50]? And [-1.50] ?

  • @jonnyawright
    @jonnyawright Жыл бұрын

    The 🐐 Dr. Mike Pound

  • @General12th
    @General12th Жыл бұрын

    Hi Dr. Pound! Hi Sean!

  • @bluegizmo1983
    @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

  • @gameteindifference2350
    @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.

  • @Barnaclebeard
    @Barnaclebeard Жыл бұрын

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

  • @poorusher
    @poorusher3 ай бұрын

    Amazing

  • @theilige
    @theilige Жыл бұрын

    whats the difference between preprepared sequences and rainbow tables?

  • @DarioVolaric
    @DarioVolaric Жыл бұрын

    Never thought Computerphile would be talking about Logjammin' :D

  • @jimiwills
    @jimiwills Жыл бұрын

    Brilliant 😊

  • @salvador1683
    @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?

  • @user-eq2ug7in7b
    @user-eq2ug7in7b Жыл бұрын

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

  • @paultapping9510
    @paultapping95108 ай бұрын

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

  • @mushroomcrepes4780
    @mushroomcrepes4780 Жыл бұрын

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

  • @adamdude
    @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
    @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

    @threeMetreJim

    Жыл бұрын

    A bit small, but no worries? Can't work out why anyone would bother to bring that up.

  • @DimonStahlmann
    @DimonStahlmann Жыл бұрын

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

  • @divitu
    @divitu Жыл бұрын

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

  • @SizarieldoR
    @SizarieldoR Жыл бұрын

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

  • @FalcoGer
    @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.

  • @gameeverything816
    @gameeverything816 Жыл бұрын

    Neat. And terrifying

  • @wChris_
    @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

    @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.

  • @mr.greengold8236
    @mr.greengold8236 Жыл бұрын

    Please make a video on ring signatures and RingCT.

  • @kmturley1
    @kmturley1 Жыл бұрын

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

  • @1992jamo
    @1992jamo Жыл бұрын

    5:16 hurt my brain with that artifact.

  • @ejonesss
    @ejonesss10 ай 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.

  • @metalcake2288
    @metalcake2288 Жыл бұрын

    Computerphile is ahead of the elliptic curve

  • @Amonimus
    @Amonimus Жыл бұрын

    Not the malicious purple pen!

  • @autohmae
    @autohmae Жыл бұрын

    Man I feel nostalgic now 🙂

  • @BIGDAWGSUZZY42069
    @BIGDAWGSUZZY42069 Жыл бұрын

    Sweet

  • @gdclemo
    @gdclemo Жыл бұрын

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

  • @daveash9572
    @daveash957210 ай бұрын

    Is it just me, or is the frame rate of the overhead camera much lower than the main camera?

  • @zxuiji
    @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.

  • @tr48092
    @tr48092 Жыл бұрын

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

  • @lobsterjass
    @lobsterjass Жыл бұрын

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

  • @htho7438
    @htho7438 Жыл бұрын

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

  • @parkpatt
    @parkpatt Жыл бұрын

    10:45 blew my mind... it's the same number every time?!

  • @aseq2
    @aseq2 Жыл бұрын

    Was the over the shoulder camera footage generated by openai?

  • @edhouse4826
    @edhouse482611 ай бұрын

    So when on Sept 10, 2001 they said they lost 2.3 Trillion dollars, i wonder how many heavy decryption machines were made?

  • @scaredyfish
    @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.

  • @AndrewFrink
    @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

    @monkyyy0

    Жыл бұрын

    Encryption grows at 2^n 2000 bit encryption wouldnt be broken

  • @s1l3nttt
    @s1l3nttt Жыл бұрын

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

  • @shanematthews1985
    @shanematthews1985 Жыл бұрын

    I mean, as a client, i always notice the small P

  • @ciano5475
    @ciano5475 Жыл бұрын

    The frame rate is slow but the image is very sharp, I think is better than the usual

  • @MrSonny6155
    @MrSonny6155 Жыл бұрын

    Guys, CCTV POV is an artistic choice.