LogJam Attack - Computerphile 

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

Nothing like a new Mike Computerphile video :D

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...

2.5fps with that smooth transition is absolutely trippy and satisfactory. Especially when writting, the text just pops up into existence randomly, amazing

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’

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

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

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.

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

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

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

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

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"

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.

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.

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

I could listen to Mike all day 🎉🎉

Mike's explanations are just the best everytime

The Canon subplot was fun

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

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

appreciate the unexpected bonus content about FPS issues :)

This is absolute gold. Many thanks Dr. Mike😊

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

Thanks for the very clear presentation.

Love Computerphile videos. Keep up the good work.

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

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

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

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

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

These guys are freaking awesome!

Mike, the hero of explaination.

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

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

I see the poundmiester, im watching it

Mike’s taught me more than all my professors combined

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

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

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

I love this channel. Fascinating stuff.

There is nothing more devious than the malicious purple pen.

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

Finally Dr Mike Pound! Love the guy :)

This video have amaizing "dreamy" vibe in it.

I love this guy!

Mike delivered as always.

Log Jammin is a highly underrated film by Jackie Treehorn

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.

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

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

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

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 :)

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

Brilliant 😊

Hi Dr. Pound! Hi Sean!

Amazing

The 🐐 Dr. Mike Pound

Never thought Computerphile would be talking about Logjammin' :D

These things make me wonder if there are already similar attacks done and most importantly the threat of storing data to decrypt later.

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.

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

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.

whats the difference between preprepared sequences and rainbow tables?

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.

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?

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

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

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.

Man I feel nostalgic now 🙂

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

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

Computerphile is ahead of the elliptic curve

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

5:16 hurt my brain with that artifact.

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

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

Neat. And terrifying

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

Not the malicious purple pen!

13:21 "The prime is ... 2^894 times by pi" How is the number prime, when one of its components is pi?

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.

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

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.

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

Please make a video on ring signatures and RingCT.

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?

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

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?

Sweet

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

Guys, CCTV POV is an artistic choice.

Damn my computer is not working good anymore. The video is stuttering and lagging.

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

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

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

Was the over the shoulder camera footage generated by openai?

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