The unsolved math problem which could be worth a billion dollars.

No one on Earth knows how to reverse one of the most popular computer algorithms. Yet it's really easy to compute one-way. You could make billions of dollars if you solved this mathematics problem, which is computed quintillions of times per second in the race for mining Bitcoin. SHA256 has some amazing properties, is useful for digital signatures, cryptography, authentication, and is a central part of the Bitcoin protocol.
(**** UPDATE 2021: After two years, I've finally posted a follow-up video, an introduction to Bitcoin. You can find it here: • Intro to Bitcoin - Is ... )
Bitcoin and other "crypto-currencies" rely on one-way hash functions like the SHA-256 algorithm to secure the blockchain where all the transactions are kept.
In this video, I explain some of the big-picture ideas behind this one function. Other cryptocurrencies use similar ideas.
Comments, suggestions, or errors? Let me know in the comments, and I'll fix them in an upcoming follow-up video.
Take a look at some of my other videos: • Matthew Weathers Teaching
--- Links -----
Wikipedia about SHA-256:
en.wikipedia.org/wiki/SHA-2
Current Bitcoin difficulty:
www.coinwarz.com/difficulty-c...
Big number calculator:
defuse.ca/big-number-calculat...
--- Credits ---
BitCoin & Money Photo:
Copy Link to Credit: (CC-BY 4.0) Cryprocurrency360.com
www.flickr.com/photos/bitcoin...
Bitcoin mining farm:
(CC-BY 2.0) Marko Ahtisaari - www.flickr.com/photos/moia/
Fourier Transform Graph:
(CC-BY 4.0) Jake
pgfplots.net/tikz/examples/aut...
Wikipedia Hash Function Algorithm illustrations:
en.wikipedia.org/wiki/SHA-2
(CC-BY-SA)

[@UmairKhan_x]

He's so fresh and tired at the same time

[@agentsd3428]

Why is this so true?

[@jimmy2895]

his upper face is tired, the area around his mouth looks young and fresh

[@chromax1619]

just like any college student

[@realdragon]

Students when they have presentation after 5 hours of sleep

[@zyxwfish]

😂

[@dizzzyjr]

Why do I feel like I have to submit my essay to him till tomorrow?

[@Entyipo]

Because you actually have to.

[@stodgycone5849]

@@hi_is_this_clorox_bleach ?????

[@Entyipo]

@@stodgycone5849 Don't pay attention, it's just a troll.

[@MoviesSlayerPoint]

@@hi_is_this_clorox_bleach I am going to report you. And I am letting you know that. 👍

[@hi_is_this_clorox_bleach]

@@MoviesSlayerPoint I may not be the hero you deserve but the one you need

[@icarus-wings]

I will always watch these videos just in case for some odd reason I immediately know the answer. Still no luck yet again.

[@bhujangjadhav4631]

Underra Ted af

[@davidspasic8623]

Lmao reletable😂

[@delubiod1970]

Me too.

[@GabrielsEpicLifeofGoals]

I think we all do XD

[@M.N.Baxter]

Lottery for math geeks

[@gatti3933]

this guy seems like he hasn't slept in a month but got 12 hours last night

[@TheXavir99]

Yeah we also saw the most liked comment

[@gatti3933]

@@TheXavir99 what

[@milanstevic8424]

@@gatti3933 "He's so fresh and tired at the same time" has 3K likes

[@wuffalo]

@@milanstevic8424 how observant of you. might you like to inform me on the colour of the sky and grass as well?

[@tyrone6820]

Imagine just rewording top comments for likes. You never trust someone named Garrett. What a tool

[@rudeusx5645]

Me clicking a video that has “MATH” in its title must be the proudest moment of my life.

[@komkodachi3173]

Hahaha ong

[@jockin]

@@hellosurname4128 haha

[@saadaqmaxamd3351]

@@hellosurname4128 🤣🤣

[@mohammedasif5877]

And u exactly have 256 likes

[@damilosky]

LMFAO 🤣🤣😂

[@krono6606]

me: “hmm maybe i could be the one to solve it” me after seeing the problem: “yeah, i don’t think i want to”

[@fate6535]

exactly

[@-.-_-.-_-.-_-.-_-.-_-.-_-]

*Can

[@gabe5225]

dunning kruger effect

[@user-gt8dh7qj3w]

imagine those numbers on your bank account

[@SavvySaxy]

Ikr same

[@BrockPlaysFortnite]

7 billion people on the planet and only 1.8 million of us have seen that number 😎

[@vistakay]

But have you ever seen 69420?

[@jaadmaan8156]

Some people would have seen the episode more than once and some people may have watched it with other people, the reality is we don’t know how many people have seen it 🧐🧐🧐

[@lez7746]

Holy shit man this is historical.

[@FakenameStevens]

Wait until you see a deck of cards!

[@jumpmanzach9208]

2.1 million now

[@plzentertext]

Found this video on my recommendations, I have never seen such a simple and clear explanation on SHA-256 in such a short amount of time. I even learnt something new from this! Wish I found you sooner (Would have saved me a couple hours :'D), you're a blessing in disguise, thank you so much for making learning easier🙏🏻

[@MatthewWeathers]

Thank you. I appreciate hearing that.

[@lorenzodiambra5210]

​@@MatthewWeathers4:41 so while people are starving some work to undermine these shits?

[@Gamert80]

​@@lorenzodiambra5210have you heard of something called coherent English? You should try it sometime.

[@justgame5508]

“Which is worth somewhere between $12 and $12,000,000” a nice nod to the volatility of Bitcoin😂

[@dexio85]

@Marty Kaspik There will be no Bitcoin in 30 years - it will be long replaced by something else or the whole idea of crypto will die altogether.

[@dexio85]

@Marty Kaspik No.

[@user-wv1in4pz2w]

@Marty Kaspik even IF crypto remains the thing, you can't know for sure if the valuable one will be bitcoin or some other cryptocurrency.

[@WhosBound]

@@dexio85 fiat will die long before crypto.

[@dexio85]

@@WhosBound Sure, keep believing that hahaha.

[@PhoenixLive_YT]

1:57 everybody Gangasta till numbers hit the "Virgintillion"

[@kry0cera962]

lmao

[@simonmultiverse6349]

"vigin" not "virgin" ... got something on your mind?

[@maxsageder9395]

@@simonmultiverse6349 someone definitely got the joke...

[@gb.buenoo]

@@simonmultiverse6349 you’re the definition of a virgin

[@nightcrawler2126]

@@simonmultiverse6349 i think it's u buddy (buzzkill alert)

[@denilsonmoreira8667]

One of the most interesting and surprisingly inspiring videos I've seen in a while. Thank you, sir!

[@kalumbumumbi09]

This video is from 2 years ago and after all the information about the SHA algorithm, the last part is actually the best part. Love it and subscribed it.

[@force6769]

Professor, You're a blessing in this world of wild pseudo-intellectual youtubers. I just found you, thanks for existing.

[@MatthewWeathers]

Thanks! That's the most interesting compliment I've gotten all day!

[@purdysanchez]

@@MatthewWeathers, sounds like blockchain-bro got butt hurt when you commented on the volatility of bitcoin.

[@internetceo]

@@Luiz1179 I have Dash, but nothing is more secure than btc. Btc is stupidly insane secure. That's the whole reason for Alts.

[@Luiz1179]

@@internetceo hey dude, bitcoin is old tech; bitcoin has no chainlocks. bitcoin and ethereum are controlled by chinese miners as a result of the mining pool concentration.

[@marco281669]

Professor, what classes should I take to learn more about that?

[@lf-domino7876]

1:57 I seriously feared that he was going to read it all

[@renecapistran484]

I was looking forward to it

[@rex198]

@@briishman8866 tommy stan lmao

[@jameschristopher2540]

@@rex198 ok

[@-Me_]

@@briishman8866 danny devito

[@dharnasahu2506]

I literally skipped 20 seconds

[@AssFaceNFT]

This was by far one of the best youtube videos I have ever watched. Explained so well! Thank you sir!!!

[@AssFaceNFT]

Im only 47 seconds in and i know i can safely say this and be amazed by the rest!!!

[@Vividxful]

You did an amazing job in this video. I've taken this as a hobby in my spare time. Thanks for making this.

[@shooketh5904]

"...billions of dollars could be at stake." **proceeds to play upbeat music**

[@benlarson9303]

Never seen this guy before, but he has the makings of a national treasure, the likes of Bob Ross and Mr. Rogers.

[@1x0x]

he looks so familiar but idk why lol

[@ushergold5149]

@@1x0x think he resembles Mr bean lil bit

[@thesonofdarkness936]

Kinda has "Nas Daily" way of speaking...

[@ritswik]

and MrBean 😂

[@musa2775]

@@1x0x Bill Murray vibes.

[@xKINGxTUTx]

I love the structure of how you explain things definitely subscribed

[@math3697]

Simplicity equals great explanation! Awesome video!

[@tommyplays5436]

I wanted him to finish reading the number out.

[@MatthewWeathers]

I'm thinking of making a video that's just that - me reading the whole number. And actually, I'll probably do one for 2^512, too, since that's another important number in cryptography.

[@owenlee9474]

@@MatthewWeathers subscribed!

[@udeshkumarganesan7040]

@@MatthewWeathers I never passed in Maths for almost a year during my high school days ( Approximately 8 exams in one year). Now, I imagine what will I be , if you were my maths teacher at that time. By the way your channel is very worth, professor. Thank you !

[@salman.sheikh]

Matthew Weathers please do!

[@llurs_]

Teacher: "the test isn't that hard" The test:

[@joshua_dlima]

enjoyed it man!! how lucky are those kids who get to be taught by a prof like you!!

[@wowleague6779]

Felt smart watching this, thanks Matthew!

[@ibrahem891]

I wish my university professor was like this in explaining . they make it more complex instead of making it more understandble .

[@levi_exiled8579]

SAMEE. I hate my math professor for that. He can't explain nor understand us. Sucks.

[@nfly1259]

If they explain so said subject in a complex way, then it just means that they dont understand so said subject enough to teach it

[@menyasavut3959]

so, tell me, have you understood how SHA256 works, by watching this video?

[@realdragon]

One day one mathematician will solve this problem and be like "That was fun, time to post my results so anybody can see it"

[@thomb.9013]

*after mining like 100million of bitcoin and claiming they had a extremely powerfull super computer

[@gergelyjakovac3063]

It might be theoretically impossile to compute the inverse of the hash function in a feasible time. It would mean that no mathematician can figure it out ever.

[@realdragon]

@@gergelyjakovac3063 Not with that attitude, if millennial problem can be solved this also probably can be solved

[@elib2670]

Couldn't be more apt

[@TomGalonska]

@@realdragon Well, that's exactly the point. If p != np holds true, which is one of the unsolved millenial problems, it would be impossible to reverse SHA256 in polinomial time. And we shouldn't worry about SHA256, that one looks pretty solid. We should worry more about RSA, which would be completely vaporized if quantum computers ever get feasible.

[@LeonardoGPN]

I loved this video, this guy wrote an amazing text before recording. Going to see if he has available books right now.

[@MatthewWeathers]

Thanks! That's high praise. No, I haven't written anything. But I'm flattered that you went looking for them.

[@RSLT]

👍 Just watched the video and I loved it! Hit that like button and subscribed to your channel. Can't wait for more amazing content like this! Keep up the great work! 👊😄

[@zs2977]

Feel like if you found a way to crack this algorithm it would be worth a lot more than a billion dollars

[@soylentgreenb]

The value of bitcoin would collapse to exactly zero very, very quickly. But you might be able to sell it to the NSA and similar TLAs. It is a solved problem though, there are two algorithms to do it that require ~4000 qubit quantum computers, but those are a couple of years out.

[@Lrripper]

@@soylentgreenb damn bitcoin is going to crash when that happens you think ?

[@Lrripper]

@@albertodona8789 yeah but quantum computers will only be owned by 2 entities. They cost millions and requires experts to run.

[@gewoonfrank478]

It would probably cost you your life

[@Artur-fw5qu]

Nah miners could update the bitcoin code and make it resistant to quantum computers, don't worry too much.

[@roshantjoy4871]

I am sure, someone should have got it in stack overflow

[@mukhamediyarkudaikulov2453]

ikr a bunch of idiots sitting at their desks all day failing to google it smh

[@marciolucena4999]

Hahahahaha i'm sureee

[@hotshot17225]

They'll just shit on you and tell you to use search, the question was already answered.

[@orlovsskibet]

Possible duplicate comment.

[@michaelszabo3071]

@@orlovsskibet 🤣😂🤣😂🤣

[@Passco666]

Vertly clear and fast explanation of huge topic. Many people spending hours on video explaining somethinf and still is no my clear for me but here I get it.completely

[@Damian_Hunt]

I watched, I listened, I studied the images........I still haven’t a clue what this is about!

[@adamtadros1472]

You are so talented for explaining this idea in a way that's not only interesting, but makes sense

[@flipflopsforlife3105]

Imagine the way to reverse it is by not doing anything but wait

[@PenguinKnightilia]

: Quantum computer enters the room : Exits at the same time

[@gillesbkf4315]

Because it solved the problem that quickly

[@EM3SonSon]

@@gillesbkf4315 Yesn't

[@benjaminakrish]

Because superposition.

[@martiddy]

When I run my code in a quantum computer it will run successfully and crash at the same time.

[@stevenchristy6156]

Is the quantum computer dead or alive?

[@TheOneHandedCooksman]

This was a great watch. I slowly find myself watching more videos that have to do with Cryptography and Algorithms moreso now that I'm enrolled in school.

[@MatthewWeathers]

Thanks. I made a couple of follow up videos about cryptocurrency in general. See the latest two videos on my channel.

[@onakitokiful]

Incredible explanation, not inteded to be technical which could be messy for begginers, but an explanation for everyone, good job

[@samuelking4723]

2:30 - I’m gonna destroy an alien society by changing this zero to a one

[@gmrn3014s]

that just made a lot more sense

[@daredevil6145]

its 'waba laba dub dub' reference, lol

[@joeydii2434]

clicking on this video as if I'm going to solve the problem XD

[@gavinaldridge1512]

3:15 I remember writing these numbers down in third grade and not knowing why at the time. It is clear to me now

[@Cookie-ht6my]

Why this in my recommended? I don’t even like math nor understand it, but somehow this guy kept my attention for 5 minutes straight and I was interested. His explanations are so easy to understand.

[@ii7mdj_353]

This video is underrated.

[@Counterstrikeenjoyer]

Indeed

[@issa3760]

@UCG9zvV-DlBQlSxjIFe8RWHA 😐😐😐

[@sleclerc87]

Very nice video! I'm glad I checked your work out. Have to agree with previous commentator that this is one of the best overviews on this very interesting topic. Keep it up :)

[@etiennejulius1179]

I love the ending. 😂. Thanks for a great video. 👍

[@noonelast8458]

Fast, precise, understandable .........smart & very expresive way to deliver information .thanks.

[@MatthewWeathers]

Thanks! That's my goal. See the follow-up videos about Bitcoin and cryptocurrencies for more info.

[@Complexity03]

This was actually quite an interesting video. I'd hope to see more like this in the future!

[@freeus6085]

This is the best youtube video I have ever seen... literally, this video filled me with child like wonder again, I am motivated again!

[@anthonyjulianelle6695]

Great explanation of what a hash function is as well of SHA 256

[@Tikolu]

Amazing explanation! I always thought I knew everything about hash algorithms but you just explained it so much more clearly.

[@YREHCorp]

anyone else thinkin "aight imma get to cracking sha 256 right now"

[@ramanpalyal]

I saved the video, so I can solve it in my free time

[@LSD123.]

I can barely navigate the internet, i got no hope...

[@gimme_ur_ass1738]

You explained everything so well

[@guyallen2355]

This is such a great video! Thanks

[@AuriPigeonery]

Math teacher teaches you how can you mine bitcoin faster. Love it

[@chocola3538]

To mine Bitcoin Faster Try Block chain👌🏿

[@orangeboy97]

He has a computer science degree so it makes sense

[@melodykuromibebbies2138]

@@orangeboy97 he does? :)

[@staborter1397]

Are you from Lithuania cuz im from Latvia and we use "ū", but LT usually use "as" in the end of the word?

[@paulgoogol2652]

Nope. He just says that it could make you very rich if you found a faster way to do it.

[@anonymouszebra1239]

This is just...So clearly explained. I wish University courses included the quick revision of easy concepts as they explain more complicated ones. Makes things so much more smooth, and makes jargon less intimidating and confusion.

[@abrahamsanchez7455]

It’s so funny I see this comment everywhere here it’s true tho they needa teach better smh they should watch these type of videos to use for examples

[@rodrigossouzadecastrodesde1280]

Congrats! Good video!

[@MegaBruceh]

"The Unsolved Maths Problem" The professor is a brilliant mathematician which is ONEderful. He can also make amusing interesting videos, which makes him TWOderful, but the title of the video misleads me to think there is a problem that you might be able to solve if only you are clever enough. Well, to solve it, you only have to process 256 bits of data, about 32 characters of the alphabet. If you let your computer run wild on it, it can't take more than a few hours to unravel that data in every possible way? Then he explains, much more clearly than I could, that the SHA algorithm maps an infinite set of input data onto a finite set of 256 bit strings, which means that SHA is an information losing process, and therefore not reversible. Fortunately, I realised this just by luck, else I could have wasted the rest of my life trying to 'solve' this non-existent problem, like those alchemists, who, in my childhood days, were trying to create gold from processing base metals.

[@InTenMinutes1]

Man, I have never been so excited to learn coding and math. You explain it very well and very simply, which shows you clearly understand it well yourself. Thank you sir.

[@yogipg2022]

even though i already knew this stuff, it was explained so awesome that i felt like i learned it all over again!

[@user-bp8zs9iu3n]

Thank you for interesting topic!

[@arpitpatel5814]

Excellent explanation. Thank you🙏🏻

[@MatthewWeathers]

Thanks. Glad you found it useful.

[@ferasalnafouri6183]

Me : Forwarding 10 seconds after he started saying that BIG number . Professor : You've got the idea 😁😁😁

[@rohanofelvenpower5566]

its only the 24th pair.... (counting from 0 :D)

[@MOGE_]

same lmao

[@waldo3035]

we are all the same

[@Official_Zim]

Literally the exact to the dot what happened to me first thing I see is numbers and hear u get the idea

[@Bobotv1000]

I learned so much in such a short video. Thanks Prof!

[@lutronc4412]

You learned false information about bitcoin. 21e8

[@austinh3848]

I learned something today. Good video

[@cyou4638]

There is a mistake in this video. For SHA256, it is possible to have the same output for two different inputs. The reason is quite simple: the output, despite its huge number of possibilities, is a fixed number, while the input can be unlimited. Therefore in theory, not only two inputs can produce the same output for SHA256, the same output can be mapped to unlimited number of inputs. Of course in practice, that different inputs produce same SHA256 output is very rare. But as a programmer I have heard anecdotal stories of software bugs assuming a hash function always produces different outputs for different inputs, but produces the same input.

[@MatthewWeathers]

You are right. I explained this difference between theoretical and practical in the pinned comment in more detail.

[@johnnytohme1]

yes older SHAs have been deprecated for that reason, you could brute force someone's password with a completely different password that has the same Hash result

[@suzj8287]

This is really fascinating, thank you!😄

[@rhpmike]

Professor Weathers literally changed my life with a sunk cost lecture. It's always nice when I accidentally stumble upon another one of his videos every few years. I'll always be indebted.

[@MatthewWeathers]

Mike! How's it going?!? Yes, I remember that lecture vaguely. I'm glad you like my videos.

[@ridearodeo8858]

Can you please share the link to the lecture Mike?

[@rhpmike]

@@MatthewWeathers Doing well thank you! Glad to see you're still sharing your passion with students. @Ridearodeo sorry it was an in-class lecture that I don't believe was recorded. It wasn't even the subject matter of the course. I'm genuinely unsure of what led Weathers to teach the topic, but it landed at a critical turning point in my life.

[@MatthewWeathers]

@Ridearodeo I don't remember exactly what I said, but I was explaining the Sunken Cost Bias (or Sunk Cost Fallacy). Here's a video that explains the concept well: kzbin.info/www/bejne/fn6liICahZVgqsk

[@ridearodeo8858]

@@MatthewWeathers thank you very much Matthew

[@iamsachin619]

Liked and subscribed already your fan!

[@God-vl5tk]

5:48 When I put all my effort trying to make a 5 year old laugh but he walks away poker faced.

[@northrocks]

Decoding SHA would be like revealing everything you ate, everything you pooped, breathed, energy spent, cells shed (or gained), at the exact positions of your body at a specific point of time to show you how you looked like as a baby (or not)

[@robertpendzick9250]

A star trek transporter, glad this problem is solved in the Star Trek time line.

[@NightmareCourtPictures]

Ya exactly. Everyone that understands chaos theory, knows that SHA is computationally irreducible, and that it can never be solved.

[@NightmareCourtPictures]

@Kasper Thörnsten I mean okay sure...it can be solved but it will take googlplex years, or a computer the size of a couple galaxies.

[@NightmareCourtPictures]

@Kasper Thörnstenno sir, i didn't miss the point you just don't know what computational irreducibility is. There is no "practical" way to solve the problem...you'd have to build something...probably bigger then computational power of the universe in order to solve them in a time frame that is within a practical time-span. The universe is computationally irriducible...means you can't build something computationally bigger then the universe to solve this problem...ie it's BASICALLY impossible to do... like the OP said, it's like going back in time tracking down every single atom you've ever shed and reassembling those atoms to create a picture of you as kid...it would take EONS to solve that kind of problem even with way better computers then the super computers of today.

[@timothyblazer1749]

You could in theory do a geometric solution, but the set would be infinite. You couldn't determine the arrangement of unique inputs that created the hash, but you could define the set of all possible solutions. Not terribly useful, but true. To Point out...the problem presented isn't precisely "reversing" a hash either. It's finding a bounded match.

[@killamankaze]

This is one of those videos you wish you could like and favorite twice...So succinct and informative. 👍

[@robertpendzick9250]

Every time you like it you change its SHA256 number so is it the same object that you are liking or a new one?

[@nicolas5540]

Excellent explanation! Thank you!!

[@MatthewWeathers]

Thanks! I appreciate hearing that.

[@bbnCRLB]

This is very educative. Thanks.

[@ieatnoodls]

this was so well explained i haven't done any reall math in longer time and could understand everything thanks very much

[@MatthewWeathers]

UPDATE 2021: I've finally made a follow-up video, describing the basics of Bitcoin: kzbin.info/www/bejne/gqvLe52Jh8aXa6M TECHNICAL NOTE / ERRATA: Several viewers have pointed out that this sentence is *technically* false: (1:31) "First of all, the only time you ever end up with the same hash, or the same fingerprint, is if you started with the exactly identical input." They're correct... on a theoretical / mathematical level. But in the *real world* on a practical level, the probabilities are such that these kinds of "hash collisions" are pretty much impossible. That's why I explain this in the next sentence: "There are so many different possible fingerprints that no two inputs have ever ended up with the same fingerprint, and I mean never, in the history of the world." (See discussion about collisions at en.wikipedia.org/wiki/Cryptographic_hash_function) For context: even if every single atom on Earth could hold a different input, that would still only be about 10^51 different inputs. The number of outputs is about 10^77, a number 100,000,000,000,000,000,000,000,000 times larger.

[@rowanhardman6736]

Fair enough for coming back over a year later to correct your viewers, respect👍

[@byondfinity2538]

um, hello, may i ask, does all this uh "preciseness" means or suggest an inrelligently designed universe? i mean, does it mean God exists? plz reply, txx

[@TheImmortalArmy822]

@@byondfinity2538 not exactly, but it really just depends on your view. Most religions are based on faith, which is believing something even though it can't be proven true. Nothing can prove that a god exists unless he came down and personally told everybody, but that would eliminate the whole point of faith, eh? If you believe that the universe is so precise that a god must have created it, you keep on believing that, but if not, then don't. Like I said, if the existence of a god could be proven, then the entire aspect of faith would become void.

[@LukasThyss]

@@TheImmortalArmy822 what a nice and respectful reply! good stuff☺️

[@NoEgg4u]

@@rowanhardman6736 The host did not correct his viewers. He made an excuse for why his claim was invalid. There are an infinite number of files that can exist (so much for the number of atoms), whereas there is a finite number of hash results. Finding the hash collisions is a daunting task. In fact, if something is impossible, it is today's computers having no where near the computing power to take on the task of finding collisions. That does not mean that the collisions do not exist. They do exist. They have to exist, because there is no maximum number of files, yet there is a ceiling on the number of hash values.

[@quosswimblik4489]

Just convert the problem into 3-sat and then convert that problem into an Omni symmetric problem like sudoku and use circularised direct determination and also reduce the problem into two problems which coordinate falsification of the main problem and with circular rules help to reduce the problem to something quickly solvable.

[@TeaBroski]

First time viewer and I love this man

[@kewlnes987]

Very interesting video, subscribed. I've always wondered what makes a hash value a bitcoin. I havent ever seen anyone ever explain this complex stuff in this easy to understand way. I'm sure you are a fantastic teacher, your students are lucky to have you!

[@saurabh945644]

I think 3blue1brown have very simple and detailed explanation.. much better than this.

[@ElonMusk-FanZone]

I already figured out the answer years ago!

[@nameless.8056]

yeah sure lol

[@HarryJurtz]

Ok Elon musk

[@HarryJurtz]

I bet you used hacks

[@ohz4191]

That is how you got rich 🧐

[@Mr.PM1993]

haha very funny Elon

[@joedarkmatter5051]

The last "dramatic" part is total win! :-D

[@dylancode]

I'm fairly sure this is a problem similar to P vs NP, a problem that says "if a problem is easy to do forwards, it it just as easy to do backwards?" In this situation, it means "can a hash easily be reverse engineered?"

[@NergusFlame]

It is actually impossible to do a reverse of pretty much any hash algorithm just because there are infinitely many inputs that produce the same output. For crypto mining you only need to find ONE input that results in only a PART of the hash. Anyways, there are clearly functions that are mathematically irreversable, even simple ones like the logical operators (OR, XOR, AND...). I don't understand how that's similar to the P=NP problem.

[@SpeedyVV]

Best KZbin performance I've seen. In a long time!

[@Brainisnotacomputer]

Brilliantly done! I loved it.

[@DBZgucker]

Cool Video 😂 especially the end where you run from the nsa hahah

[@tuckersossaman4485]

This was absolute gold standard content!!

[@MatthewWeathers]

Thank you. That's very kind.

[@Sean.Vosler]

I’m glad there are smart people out in the world to work on this stuff, whatever it is

[@disobeytoday4685]

The only thing I learned from this video was the conspiracy theory at the end. Even when I try to get away from conspiracy theories, they follow me around.

[@sonalidutt7704]

2:02 Him not reading all of it hurt my soul

[@mayurgudi381]

🤣🤣🤣

[@tenzek4635]

Wait for the director's cut.

[@iamsadiq024]

Thank you very much. I enjoyed watching the video.

[@MatthewWeathers]

Thanks. Glad you enjoyed it.

[@anglictinavojta1674]

"You explain things in a way so I can understand them" - Me, paraphrasing Forrest Gump

[@lasersss8588]

It’s crazy because Mathew weathers started KZbin in the year of 2006

[@brianfreeman2500]

Coolest computer science professor I ever had in college, Matthew Weathers. Hat tip, to you sir. 🎩

[@MatthewWeathers]

Thanks, Brian. You saw this Bitcoin video before it started getting thousands of views in the past week.

[@zaur66]

I like this video , nice explanation. Thank you sir!

[@Minicraftiano]

4:58 As a way to see the increase in performance, BTC total hashrate has peaked 180EH/s this year. 3x faster compared to 2019!

[@useazebra]

Passwords are typically saved as hashes because of the presumed security to doing so. However, some common hashes have been reused with default seeds for so long that we can actually do reverse-lookups of known passwords. People have pre-computed the hashes for all possible passwords with 6-13 (ish) characters and compiled them as "rainbow tables" which can be used to look up a password based on the hash. Which is why from a security admin perspective, it's important to change the default seed used in your hashes, and from a user perspective it's important to not reuse passwords.

[@cat47]

well, you would actually want to use a _password_ hashing algorithm like bcrypt or argon2. Bcrypt, I know, has builtin password salting and you can very easily change the amount of time it takes to hash a password, meaning that even if someone got a hold of your hashed passwords, in could take anywhere from nanoseconds to years to crack your password, depending on what difficulty level you choose for your hash, though realistically one would use somewhere around two seconds. Two seconds is a very, very, long time compared to nanoseconds for a sha256 hash.

[@relaxwithai]

This is one of the most simplified and well explained SHA256 algorithm explanation i have ever come across. I instantly liked the video just few minutes in. You are a great teacher. If i was to advise anyone to attend Biola Uni, it will be because of you. Keep up the great work, will love to see more videos like this (or the airplane haox debunking video) cause April fool is just once a year and i love really your content :)

[@MatthewWeathers]

Thanks! I appreciate the feedback. I'm actually at VidCon today (the annual KZbin conference in Anaheim, California) learning about making better videos more frequently. So hopefully, you'll see more in the coming weeks!

[@relaxwithai]

@@MatthewWeathers That's great news. Can't wait to see more content from you :)

[@idleeyez1646]

I thoroughly enjoyed this

[@MdAshrafurRahman]

wow !! Very interesting explanation, easy to understand

[@Aruesx]

I was with you for the first 30 seconds but then I was completely lost the rest of the video.

[@jackwang8923]

Love the info!

[@bensonantony2565]

I liked the way you presented 😁

[@SycoticSociety]

This video will still be relevant 20 years from now.

[@geekionizado]

This video is really good and funny, thanks :)