I have a master's degree in computer science, and this is the best explanation of RSA I can remember coming across.

Man... This is the definition of a good teacher. You can explain things very well and in a succinct manner. Great video!

this is the kind of teacher we all needed in school

2 hours of lecture in my uni and I didn't understand shit, 8 min of video and I feel super confident about rsa. Thanks man you a great professor

Not only did I just see the best explanation of RSA encryption that I've ever come across, I got a free yoga lesson as well.

This makes more sense than some other videos that i searched for in other places with the fictional alice and bob. Proper detail like in this video with the actual numbers is far better than other videos i've seen elsewhere

Being from Ireland, the first couple of times I heard you say "Irish say" I had to remind myself he's saying "RSA", ha ha. Great lecture, brilliant enthusiasm and clear explanation, thank you! You're not just a good lecturer, you're clearly also a fantastic teacher.

What a good teacher, you can tell the students are actually interested by how they're engaging as well.

I love how you simplify the algorithm & solution. Additionally, that was a great homework assignment to show why we can't rely on approximations stored in calculators for irrational numbers.

Some remarks: 1. The public key is (k = 5, m = 14), where 14 is a modulus (often large) chosen by the recipient, and 5 is an unit mod φ(14). Note that 5 is multiplicatively invertible under mod φ(14), and the inverse of 5 is 5 mod φ(14). 2. φ is the Euler totient function. φ(14) is the counting of positive number that is less than 14 and is relative prime to 14. φ(14) = 6 = (2 - 1)*(7 - 1). 3. The private key is the inverse of k = 5 mod φ(14), i.e. 5 mod φ(14). 4. In the video, we use 11 as our private key since 11 is congruent to 5 mod φ(14). We could use any number that is congruent to 5 mod φ(14), i.e. 5, 11, 17, 23, ... etc.

Why did I not have you as my teacher? I missed out on so much. Truly amazing teacher!

If I had a lecturer like this guy, I would ace every subject! Great job man!

Eddie, you are a genius. I am a math teacher too, and its incredible how much i learn everytime with your videos. Best of lucks in your life!

You explained clearly in 8 minutes what I couldn't fathom in a 2 hour lecture, Thank you, you're a credit to good teaching.

Every time I don't understand things in my classes in computer science, I get on youtube to find an explanation video about the topic I want to understand. And almost every time I find a video of yours. I like the way you teach and you make it very easy to understand complex things. Keep your work going man, you're great!

Watching this preping for a Master's degree - so well explained, actually got some insights from this that were not in the University lectures. For a while I was thinking something was wrong, but this actually highlight things in my notes I had failed to appreciate. Good job!

I thought RSA meant "Really Secure Algorithm"

He seems like such a genuinely nice guy. Thanks for the clear and understandable explanation Mr Woo! :)

This Video was uploaded when I was still in high school but here it is helping me out with final-year undergraduate studies. Thank you, sir

6:40 it would be easier if you divide 4194304 by 14 which equals to 299593.14... then we take the integer part (299593) and multiply by 14 which is equal to 4194302.. and now if we subtract 4194302 from 4194304 and we get 2 which is equal to number B

The simpler way to do this would be To find 4194304 (mod 14): 4194304 / 14 = 299593.1429... 14 X 299593 = 4194302 (discard decimals) 4194304 - 4194302 = 2

Australia Year 12 Graduate here. For our last part of Digital Solutions, we dove into ciphers, consisting of the basics of caesars cipher, vigenere cipher, OTP ciphers, and eventually RSA encryptions. My issue wasn't the way it works, but more of how to implement it into code. This video helped me develop a C file that could take in a p,q and a string to output an encrypted message, as well as allowing me to decrypt it. Thank you soo much for the headaches you saved me from.

Dude THANK YOU! I had a RSA algorithm problem due at midnight and I would have not been able to solve it without your guidance. Thank you for everything you do to make students lives a little easier.

This is exactly what I was looking for, makes so much more sense than all the other explanations combined.

You made something that seems super hard become super easy, thank you!

Guys I think the reason why the calculation does not give us 2 and instead gives a very long decimal 1.99999999988... is because when we divide 4194304 by 14, the answer actually is 299593.142857142857.....(I divided manually using long division), but in the calculator we get a rounded figure of .1429. If you multiply 0.142857142857.... by 14 (instead of the rounded figure like he showed), you would get a proper 2 instead of 0.999999988.... So, it happens because we round figure the decimal number and not calculate with the actually long decimal that we get when we divide manually by long division on a notebook.

I wish I had a teacher like you, wonderful explanation, your class is full of energy, you are the type of teacher that loves his job.

Never before have I seen such an easy explanation of RSA (online)! You are a good teacher Mr Woo!

I have ADHD and Im having so much trouble with my computer networking course because of how boring it is. But this guy kept my attention, Thanks

Dude you're a great teacher, you seem genuinely enthusiastic

I miss school so much when I see this kind of topics handled by a great teacher

I have doctorate in math and computers and this is the most succulent explanation on the whole internet

For anyone wondering about the exact details, the sender picks 2 huge distinct primes, p and q. The pair (p,q) is known as the private key and is only known to the sender and the receiver. They then define n=pq and work out φ(n) = (p-1)(q-1). φ(k) is the Euler Totient Function which is the number of integers between 1 and k which are coprime to k. Then the sender picks a number e such that (e, φ(n)) = 1 (e is coprime to φ(n) under this notation). The sender then publishes the pair (e,n) (or (n,e) in some conventions) and this becomes the public key. They then send a message by converting it into a number M, with M

There are many videos out there that explain the concept of public and private key in a simple way, but I always thought they were too "abstract". In my opinion, this here is a really good explanation that makes you grasp the concept in a better way, because it "dives the right amount of deep" for a initial explanation.

I am an actual professional security expert and this explanation is excellent.

Epitome of a good teacher even a newbie can grasps and with enough reps can develope encrypt decrpt skills.

This is the best explanation I have seen! You're a good teacher!! Far out!

it sucks to watch a great professor that is talented and knows how to educate be disrespected by his students like this. I learned so much this and I appreciate all your diligent work !

I love your enthusiasm and a different approach towards the topic. VIVA!!!

Have to say this, you saved my life, that's the best explanation on the web and I have to do this as a homework for tomorrow, thanks!

These students are getting a real treat with this teacher.

Great to listen to him even if you are not familiar with the RSA :)) I desperately needed this, thank you Eddie

I really cant describe in words how f***** AWESOME you are man. Ive been watching your videos since year 10 and now im in college, watching this video to clear some concepts in Quantum Computing. Thanks Eddi

Thank you so much, Eddie Woo. This is helping me for my Uni exam next week. ;) 👍🏻👍🏻👍🏻

Why are people talking while he's teaching? I don't understand.

This teacher is a amazing with his teaching skills 👍🏻

Hi Eddie, I know this video is a few years old but thank you so much. I've struggled a lot with this from watching other videos and reading about it online. This video made it so easy to understand, thank you!

Wish I had a teacher like you man holy shit. I was confused till I found you. GGs only wasted 1 day trying to figure this out and boom in 8 mins im a God at RSA crypto.

we all need this kinda teacher. He is good at explaining and is funny.

Oh man! The way you handled yourself is awesome and the lecture was so clear and perfect one i have ever seen!

The best RSA explaination i have ever seen

woo woo you are awesome . now im in second term of university and im studying Software engineering but wish i has teachers like you in school . your explanation is great and I really appreciate you . i wish you luck .

Man, this brought back memories when, for reasons unknown, YT put this in my feed. Made me remember the demo program with a silly little Windows Forms interface (hey this was over a decade ago) I wrote during my Master's at Monash and have a look at the old source code. Had to do it with "classical" random primes and then also with elliptic curves - and included Diffie Hellman for key exchange. It showed all the various steps including the "magic" going on in the background. Was one of my favourite units (and got me a HD ;). How I wish I'd had teachers like you so we would have done this in high school!

Eddie, I just wanted to say THANK YOU! This video taught me more in 8 minutes than I was able to figure out in 2 hours trying to decipher (hah) my textbook. Stay awesome. :)

Dude, I literally have a test on this in like two days. You are the best

I'm a real idiot when it comes to math. This is the only video on RSA that makes any sense to me. Thanks Eddie!

Its really a good and simple teaching which help millions. kudos

wow what a great teacher! love the enthusiasm, you can tell he's very passionate about this kind of stuff

He just hurt my brain but I see a tiny light of understanding way out on the horizon. Math guys and gals are awesome.

your absolutely incredible. idk what it is about your teaching but it just works

Never realized it is so simple. Text books make it so hard to understand! Kudos!

a - b(floor(a/b)) is a nice way of calculating modulo.

Loving his approach and enthusiasm of teaching! Thanks a ton! :) you are an amazing teacher!

u r the most conistent utuber i guess, who post video almost every day... huge respect sir

I love how digestible you made this for someone who has no idea about RSA!

it gave me two. lol - You're my favorite mathematician now!

I thought leaving high school would be the end of watching Eddi Woo but turns out he is better at explaining this than my lecturer.

Finally someone who get's straight to the point. Thank you!

The "lock" analogy is much better than the "public key" terminology. I came up with this idea soon after I learned the RSA and I am not alone. I wonder why they have not changed the terminology yet?!

Maths is too hard, I'm gonna doing some yoga.

Really loved your video and explanation. I would like to say just like any other student watching your video, keep it up.

Wtf, this genius just increased my IQ by 10 points.

Brilliant teacher.

If you can record your lessons, upload to KZfaq and pull off nearly a million views, you know you're a good teacher.

2 minutes in and I am already extremely jealous of these students.

love it, the best explenation so far

Brilliant, I just love how you took this one on.

I know it's just a demonstration but working out both (4**11)%14 and (4**5)%14 are 2 (or the original B), so you can "decipher" with either. And there are several other ways to reach the same answer, but also a pattern actually emerges (mod remainder 2, 8, 4, repeat). But I imagine that the actual math behind the algorithm is much more complicated. Thanks, cool video.

This is brilliant pedagogy. Thanks.

Encryption is doing magic with numbers

Shame such a great teacher is stuck with students who don't seem to care or see the significance.

Wow quite funny the date of the video and the date I’m watching this, lol. Anyways, that is a pretty good explanation, thank you!

I went through this video pair on RSA at least twice during my Uni days. Now watching more recreationally. Only today do I notice that there's a Yoga poster on the wall. Guess when doing Uni assignments, you are really focused on the content :D

Public Key Encryption was first developed by a Cambridge Uni graduate working at GCHQ I believe. He supposedly came up with idea on the bus to work!! Problem is, it was Top Secret so yet again, someone else later made all the money from a British invention.

Eddie, you helped me pass my Codes & Codebreaking Unit at Uni. Thanks!

Great! Now I can send ANY secret letter I like - as long as it's between A and M.

Imagine if they taught this at schools, i would’ve liked maths sooner XD

Students in this class aren't realizing that this content might go viral someday.

I have a final on this in a few hours so praying that you just got me through it!!! 🙏🏽😌

I wish I had got interesting homeworks like what you gave

How energetic and exciting! Thank you a lot!

Great explanation and great teacher! Congratulation

Eddie is such a brilliant teacher that he has to sush his students because they are busy talking *about the lesson*

1:14 is now relevant on r/dankmemes

Surely 4194304 - 299593*15 (or an easier way to enter it in the calculator: 299593 * 14 - 4194304) is a much faster way to find the integer remainder? You know there are 299593x 14s in the number, so subtract that from the original number and you have your remainder? Or am I missing something?

That was a wasted opportunity to show how mod interacts with powers and multiplication: 4¹¹ ≡ 4*4¹⁰ ≡ 4*16⁵ ≡ 4*2⁵ ≡ 4*2*2⁴ ≡ 8*16 ≡ 8*2 ≡ 16 ≡ 2 (mod 14).

What an amazing teacher!

Man, you are a genius

The reason he got 1.99....88 instead of 2 is because of floating-point arithmetic. For a computer, the fraction 1/3 does not have an infinite number of 3's, because the computer doesn't have an infinite amount of memory. When a computer stores a number into memory, if must first allocate how much memory that number will occupy (usually a power-of-two-times-eight number of bits). Then it stores as many significant digits as it can, but most of the time this means some get chopped off at the end or rounded off. As we do math with these truncated numbers, the effect of rounding errors grows.

def hash2(n, size): return (n+3)% size def hash(n, size, count=0): return n + count * hash2(n, size) % size