Will Quantum Computers break encryption?

How do you secure messages over the internet? How do quantum computers break it? How do you fix it? Why don't you watch the video to find out? Why does this description have so many questions? Why are you still reading? What is the meaning of life?
0:00 Intro - Are we DOOOOMED??
0:52 How NOT to Send Secret Messages
2:09 RSA - Encryption Today
5:19 One-Way Functions and Post-Quantum Cryptography
7:28 Qubits and Measurement
9:03 BB84 - Quantum Cryptography
12:43 Alternatives and Problems
14:26 A Case for Quantum Computing
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CLARIFICATIONS:
You don't actually need a quantum computer to do quantum-safe encryption. As briefly mentioned at 7.04 , there are encryption schemes that can be run on regular computers that can't be broken by quantum computers.
CORRECTIONS:
"The public key can only be used to scramble information." (2.18) Technically, you can use any key to encrypt or decrypt whatever you want. But there's a specific way to use them that's useful, which is what's shown in the video.
"Given a private key, it's easy to create its corresponding public key." (5.36) In RSA, depending on exactly what you mean by "private key", neither key is actually derivable from the other. When they are created, they are generated together from a common base (not just the public key from the private key). But typically, the file that stores the "private key" actually contains a bit more information than just the private key. For example, in PKCS #1 RSA private key format ( tools.ietf.org/html/rfc3447#a... ), the file technically contains the entire public key too. So in short, you technically can't get the public key from the private key or vice versa, but the file that contains the private key can hold more than just the private key alone, making it possible to retrieve the public key from it.
Video links:
Encryption and HUGE numbers - Numberphile
• Encryption and HUGE nu...
The No Cloning Theorem - minutephysics
• The No Cloning Theorem
Quantum Entanglement & Spooky Action at a Distance - Veritasium
• Quantum Entanglement &...
Sources:
Quantum Computing for Computer Scientists
books.google.ca/books/about/Qu...
Random person talking about Quantum MITM attacks
crypto.stackexchange.com/quest...
The Ekert Protocol (i.e. E91)
www.ux1.eiu.edu/~nilic/Nina's-...
Annealing vs. Universal Quantum Computers
/ what-s-the-difference-...
Images, Documents, and Screenshots:
Post-Quantum Cryptography initiatives
csrc.nist.gov/groups/ST/post-q...
pqcrypto.eu.org/docs/initial-r...
Internet map (Carna Botnet)
census2012.sourceforge.net/
Quantum network maps
www.slideshare.net/ADVAOptica...
IBM Quantum
research.ibm.com/ibm-q/
Music:
KZbin audio library:
Blue Skies
Incompetech:
Jay Jay
Pamgaea
The House of Leaves
Premium Beat:
Cutting Edge Technology
Second Time Around
Swoosh 1 sound effect came from here:
soundbible.com/682-Swoosh-1.html
...and is under this license:
creativecommons.org/licenses/...

[@frameofessence]

CLARIFICATIONS: You don't actually need a quantum computer to do quantum-safe encryption. As briefly mentioned at 7:04 , there are encryption schemes that can be run on regular computers that can't be broken by quantum computers. CORRECTIONS: [2:18] Technically, you can use any key to encrypt or decrypt whatever you want. But there's a specific way to use them that's useful, which is what's shown in the video. [5:36] In RSA, depending on exactly what you mean by "private key", neither key is actually derivable from the other. When they are created, they are generated together from a common base (not just the public key from the private key). But typically, the file that stores the "private key" actually contains a bit more information than just the private key. For example, in PKCS #1 RSA private key format ( tools.ietf.org/html/rfc3447#appendix-A.1.2 ), the file technically contains the entire public key too. So in short, you technically can't get the public key from the private key or vice versa, but the file that contains the private key can hold more than just the private key alone, making it possible to retrieve the public key from it.

[@sexismagainstmen4617]

um.... why can you only measure horizontally or vertically. you didnt explain that at all. you can measure in any plane.

[@frameofessence]

To keep it simpler, I only showed two orientations because that's what was relevant to explaining BB84. And to be fair, more orientations are shown at 13:04

[@stealth9799]

That is incorrect; in ECC, the private key (and one component of the public key) can be chosen at will however you want. With RSA, that would be correct; you choose information that derives both keys but with ECC, you pick a private key k (256 bits) at your own discretion. This could be from a CSPRNG, a hash of a picture of lava lamps or the user's password salted and run through a KDF. You then pick a public point G on the curve and calculate the second component of the public key, kG by "dotting" G with itself k times. It is easy to "dot" something with itself k times because there are shortcuts you can take but when given a starting point and an ending point, it is computationally infeasible to figure out how many times it was dotted. You have to go through and actually dot it that many times instead of using shortcuts.

[@frameofessence]

Well, this is a lot more complicated than I thought. I'll edit the original comment to be more specific to RSA. Thank you for your input.

[@stealth9799]

I just wanted to say that you did a fantastic job explaining btw. Also thanks for welcoming feedback and making corrections when new information becomes available! I wish more content creators were like you.

[@MrSeppieD]

My answer on a computer science exam: �������� Teacher: What is this supposed to mean? Me: It's the requested 8bit answer, but expressed in qubits. It represents the correct answer if and only if you know the correct answer as well.

[@magnitudefallout3944]

that one is golden

[@klkkloreklffd]

lmao

[@4TechGuns]

The characters is actually just FFFD in hex. It's not actual qubits.

[@mattontop]

@@4TechGuns Congratulations. You didn't get the joke (:

[@justincase5272]

Clever...

[@paiovezam8533]

Eavesdropper: This is the lock picking lawyer...

[@Chris_Hetherington]

Plot twist, LPL is actually Bosnian Bill.

[@bestjerk]

and today we are going to read people's e mails

[@sirhootsalot2343]

so we are going to use this quantum computer Bosnian Bill and I made

[@gamermoment3708]

"Once again an inexcusable design flaw"

[@TECHGYVERBD]

150 Likes!

[@Mrkevi123]

Me: "password123" Quantam CPU: "I'm about to end this man's whole career"

[@bucket4255]

Interesting... And what's your username?

[@eness379]

@@bucket4255 username123

[@bucket4255]

@@eness379 Interesting, interesting. Now, if you can't log in, it's because you may of deleted your account by accident.

[@codythompson9973]

@@bucket4255 Interesting Interesting Interesting. Now, what is your middle user name

[@bucket4255]

@@codythompson9973 Middleusername123

[@Int8]

Plot twist: the server is the eavesdropper

[@RyanTosh]

Plot twist: The eavesdropper is the server!

[@thejurassicwarewolf3300]

PLOT TWIST: everyone is the evesdropper

[@matthewstone2545]

Plot Twist: Everyone is, YOU!!!

[@FplusETVChannel]

plot twist: YOU are the eavesdropper

[@brownieman377]

Plottiest plotty plot plot plotty plot twisty twist: There is no servers or eavesdropper and there is no internet

[@Thomasfrank]

Just watched three of your videos, and I FINALLY feel like I have an at least rudimentary understanding of quantum computers (and classical logic gates to boot). Your videos are fantastic - hope to see more in the future!

[@Ab-cj6gl]

my man

[@twilightknight123]

As a physics grad doing research in the field of quantum computing, I approve of this video.

[@jujuyee2534]

as an astronaut i agree with you

[@Atul_Thakur97]

as an unqualified physics student...i approve both of you to teach me physics

[@pushqrdx]

as a human i say fuck you all 😂

[@anandpatel1074]

As a quantum astronaut, I approve of this comment

[@rubenverster250]

As a hobbyist of this field. I can neither approve, nor disapprove my say. Until it is said

[@matiasl.ceballos3346]

Even though this video is about quantum computers, the explanation about how RSA encription works is THE best i've found so far for someone with no prior knowledge. It helped me a lot, and I often show this video to people who are taking their first steps in networking. Great job!

[@elbozo5723]

well find a new video… he doesn’t even mention the 245 byte limit on it

[@matiasl.ceballos3346]

@@elbozo5723 Dude, I meant it is great for an introduction for someone with no prior knowledge. Not for all the details.

[@maywr3893]

true, RSA was complicated for me before this video

[@NorDank]

So the devil is reading my e-mails...

[@joseph_pokemon]

they are just programmers, network engineers and mathematicians that want to get rich no matter what xd

[@PaperBagMan884]

Well, if by devil, you mean the NSA, FBI, other three letter agencies, then yes!

[@ripperfisher182250]

Nor Dank I found this mildly humourous. 1 gold star.

[@ReallyReal_1]

Nor Dank a ton of people didn't get this joke

[@1998wiwi]

Yep. You should include a picture of a cross or something like that in all messages you send to keep that guy away.

[@Ze_eT]

"BECAUSE QUANTUM MECHANICS!" I laughed so hard.

[@silence439]

Ze_eTPlays It would be too hard to explain quantum mechanics in less then a hour, although he really wants to.

[@dylanboyd8767]

you should see kurtzgesagt's video on quantum computers kzbin.info/www/bejne/gJmrfn15itKkaJo very informative

[@ksam2000]

lmao

[@KafinSulthan]

this could be the new: "except-wait for it-the mongols" *montage plays*

[@tinycockjock1967]

Ze_eTPlays Did you laugh so hard mate? Or did you just nose-exhale?

[@Aveikin]

That was literally the best explanation of how encryption works I've ever seen. Finally I can fully understand it, thanks

[@fye7785]

It's fascinating how it actually take half of the video as an introduction, well explained. Thank you.

[@renatobritto4096]

Shit man, this video actually made me learn something hard. I find these lacking on youtube today, thanks, love this channel.

[@xetera]

You must be searching for the wrongest possible things because there haven't been as many amazing educational videos like these on youtube as there are today.

[@chinmaygupta1530]

DOGGYDOGG do you know how it works? The video is a little difficult to understand, but if you know it better, why don't you make a video and enlighten us?

[@circumplex9552]

@@chinmaygupta1530 deleted reply?

[@burnhamaj]

That was a very well-made video. I really enjoyed it. You deserve way more views.

[@savingsoulsociety]

Stumbled on this video today while randomly scrolling my recommended. I actually learned something quite interesting, thanks for this video, you explained how it works really well

[@dirm12]

I have watched so many video that attempted to explain encryption, you were the first to actually make it clear.

[@Quick_in_and_out]

So I was recently thinking to myself "will quantum computers break encryption?" Then I find this video a day later! Then I find out that your original title was "encryption and quantum computers" which I never would have clicked on! Good work all round

[@danthegreat8411]

*That's Some Magical Shit Right There!*

[@siipi6331]

Quantum computers will never break RLWE-based homomorphic encryption.

[@o4ugDF54PLqU]

Your videos deserve more views. Maybe you should try making your videos' titles more descriptive because nobody would click on a video that is named "Encryption and Quantum Computers". Instead, name it something like "Will quantum computers break encryption?"

[@frameofessence]

Good idea! I'll do that.

[@frameofessence]

Thank you by the way. I was having trouble coming up with a title.

[@boomperson818]

lol i clicked because of the "Will quantum computers break encryption?"

[@alivrah]

BoomPerson Same here!

[@user-ht3tp3uj4v]

haha , same here But I didn't even clicked for the title I just saw it was uploaded by Frame of Essence so I clicked it

[@ARoundThing]

I want you to know that I thank you for making such concepts so simple. Please keep doing what you do. You have a great channel and I really wish you best of luck. Thank you.

[@ketansaxena]

That is the best thing I've seen on quantum computing till now. Keep up the good work!

[@DJaquithFL]

Eavesdropping would become the ultimate DDoS.

[@death_parade]

This comment is so underrated.

[@kressckerl]

Irl: trying to have a secret conversation with somebody, but a third guy stands behind you and making obnoxius noises evertime you try to share your public key...

[@misceryyt2897]

what are you talking about not all cyber crime is DDos

[@madisonlink7141]

@MisceryYT and Svein: DDoS is when you prevent a sever from communicating with its proper clients (using a distributed attack) in order to deny service. In the quantum security example, eavesdropping destroys the message. Therefore, distributed eavesdropping on all channels becomes a DoS attack, because servers literally cannot communicate with their clients.

[@brazgazz]

DO YOU EVE KNOW WHAT A DDOS IS?

[@turun_ambartanen]

that was the best explaination of these encryption algorithms i have ever seem!

[@joebama7765]

can't we use quantum encryption on the quantum E-mails using Quantum Nord-Quantum-VPN? lol

[@RedGallardo]

No, it's forbidden and you'll have a camera up your butt for constant verification of you not trying to encrypt anything from people with power.

[@joebama7765]

@@RedGallardo ok

[@kadincool]

Quantum mechanics hurt my brain

[@joebama7765]

@sp of course the best cola to drink while doing pc stuff

[@saltysea3626]

And you are a quantum Minecraftr playing quantum Minecraft.

[@kepe__]

I watched this video 3 years ago. I have been looking for it ever since. Thank you.

[@Afterscience742]

First 3 CPG grey videos in a row, then Frame of Essence uploads again. I must be in KZbin heaven.

[@yomanos]

Just found your channel, it's great! Do more videos on cryptography!

[@amartyamishra6961]

This was the best video about encryption in general, I've been looking everywhere and was confused after 4 videos till I arrived here.

[@Hexation]

14:46-end. very inspirational! you changed the way I thought about some things like trying new things

[@nibblrrr7124]

Thanks for mentioning post-quantum cryptography (classical crypto resilient against known quantum computer attacks). Most tend to jump immediately to quantum cryptography, but that may only be practical in the future (if at all, for everyday use by everyone). That doesn't help against adversaries that collect your encrypted messages you're sending right now, and store them until quantum computers come around.

[@CalamityInAction]

5:17 The eavesdropper says "F YEAH!!!"

[@segmentsAndCurves]

Lol I just see you in Chopin Fantaisie op 49.

[@CalamityInAction]

@@segmentsAndCurves Haha yeah It’s a great piece

[@VincentDoesThings]

I like that you simplified this in a way that 2019 nerds can enjoy. Very fascinating topic!

[@gunjanshuvro3427]

Wow.... This is one of the best videos out there. Thanks Philip 😇

[@benjaminbrady2385]

Nice description btw

[@arock9529]

lol just before the second “ARE WE DOOOOOMED?” ,the eavesdropper goes “YEA!”

[@arock9529]

damn this was 3 years ago

[@kiddicarus]

We found this video, as well as many of the comments below, to be both educational and quite enjoyable. Thank you very much.

[@zotac1018]

I was studying its systems as part of my high school project. The way you explained encryption was better than any book I hac\ve ever read.

[@nfistfu]

The "Are we DOOMED????" animation is my spirit animal.

[@kingbobthepimp]

Because Math

[@frillneckedlizard8529]

kingbobthepimp it is actually pretty easy

[@yegfuf]

Because quantum mechanics

[@Thefuryspeed100]

Im doing reasearch on quantum mechanics and cryptography for fun, and people like you make it possible Thank you for this video!

[@zhaoxunyan4016]

Thank you for this video! Now I understand RSA perfectly!

[@ScienceAsylum]

Great video! You going to VidCon this year?

[@frameofessence]

Thanks! I can't go this year... maybe the next?

[@ScienceAsylum]

Bummer. I only ask because I'm going this year... FINALLY!

[@frameofessence]

+The Science Asylum Darn, would have been nice to meet you!

[@ScienceAsylum]

Yeah, I should have gone last year. I'm hoping to "network" this time. We'll see...

[@lua-in2sl]

The Science Asylum w

[@melody_florum]

5:14 the fact that the server is surprised is so cute

[@circumplex9552]

And the eavesdropper says "F YEAH!" for a frame

[@StatisticallyChallenged]

The videos visuals were so simple to understand alongside the commentary. Awesome Job!

[@DrakiniteOfficial]

I actually never understood exactly how public and private keys worked until this video. I swear I've watched like 4 or 5 before this one. Great explanation.

[@bryanchu5379]

BACK AT IT AGAIN

[@bryanchu5379]

first?

[@Anna-tl6oz]

Bryan Chu yep.

[@Alice_Fumo]

I'm seeing a massive problem with preserving the superposition of a qbit in online conversation: online conversations are done over several servers (ones own ISP servers, the ISP servers of the person you're interacting with) How could those qbits even be passed down between those servers without being measured? how does one of the servers even know which info to send to the next computer without measuring it? Wouldn't it have to be measured there? What this problem would require to be solved is that the info of the input buffer can be moved to the output buffer without being looked at. I guess a functional quantum computer simply implies that this issue is already figured out. A current computer in order to do that would read the information at the input memory location and put those values at another location and then delete the information at the input buffer.. or just leave it there and the next batch of input will just override it - whatever! - a quantum computer can move data around between memory areas without looking at them. I think that is an interesting thing to figure out on the physical side of making a quantum computer. At least there's the implication that all computers inbetween have to be quantum computers, thus I expect quantum computers to use their own IP range when they're a thing. Edit: Damn, the video kind of covered that this is not currently a problem. (Except that superpositions can't 100% accurately be transmitted all the time)

[@frameofessence]

I'm not really sure how this would work. Maybe the destination could be encoded in a header which is expected to be measured, leaving the rest of the message alone. It would preserve the superpositions in the message while still letting each node figure out where to send it.

[@TheDuckofDoom.]

I have no idea how qbits could be transferred long distances[even a few meters], most of the current Qcomputing information indicates that Qcomputers are more of an accelerator, like a GPU, always attached to a normal computer.

[@TheAkashicTraveller]

Frame of Essence Yeah but the qbits would by physical particles moving at the speed of light you're simply not going to have enough time to choose.

[@bernhardtrian7471]

this conversation ...... no one knows how the communication and decryption would work in wide areas , this is yet unsolved I think , even with all the protocols and information tables ( arp )

[@roboticunclephil]

headers is how current encrypted packets between servers are secured, why wouldn't it be different?

[@YalnYALNIZ]

English isn't my primary language but i understand it easily without any problem. You tell them so pure. Thanks.

[@Hisham1097]

You earned a new subscriber. Great work. Keep it up. Hoping for more videos

[@violetlavender9504]

Lemme get a Supersingular Isogeny Diffie-Hellman Key Exchange with extra sauce

[@sebastianelytron8450]

Frame of Essence would be a sick name for a progressive metal band!

[@MetaDecker]

Because Math would be a good 80's retro electro-synth band name

[@TakiRyuujin]

Make it Flame of Essence

[@abyssstrider2547]

zztop3000 Nah, it sounds delicate, soft, emotional, basically beautiful!

[@RandomNullpointer]

u mean sicc

[@htf5555]

Evanescence

[@Mr_SSK]

Thank you so much! :) Such a nice explanation!

[@mateolaguna6542]

Such a great video! You make easy to understand topics that are really hard. Thks!!

[@OnlyMisery]

"I used the quantum to destroy the quantum"

[@turboshamu]

OMG your video is so Goood!!! >

[@786sado786]

subscribed, checked your other videos and love the humor! keep up the work!

[@mikaxms]

This is such a great channel! Why did I get this channel recommended only now?

[@giu1644]

A question I expected the answer to (and didn't get) was why quantum computers are good against traditional cryptography, so I guess a follow up on Shor's algorithm would be great!

[@frameofessence]

That would be way too complicated for me! PBS infinite series did a good summary of it though: kzbin.info/www/bejne/Z2O0ZIConZVmfc0 kzbin.info/www/bejne/rYbai42XfpqoZsU

[@purewaterruler]

you might want to link to numberphile video in the description.

[@whoofianbrony8804]

This is a very good explanation of the concepts behind Transport Layer Security (TLS), the thing which kicks in when you have https configured correctly

[@thendog2679]

Love your hard work and information you put into your animations! I see big sub potential here! :)

[@HarshYadav-cj3yu]

6:00 using throttling on the network to slow it down may help evesdropper to have enough time to decrypt them.

[@cassiopeia_real]

i think it takes more time than the heat death of the universe, dont quote me on that though

[@WoFDarkNewton]

13:36 "You need to sacrifice a *BIT* more information" XD

[@goldenfire6421]

Thanks! This is really simple (enough for me to understand). Great video!

[@WannabeCanadianDev]

I'm mainly here for the primer on RSA, had to watch a couple of times but it's very useful!

[@tfr]

4:00 When you put a key in a box and lock it with a different key. 😏

[@GameCyborgCh]

0:39 someone will compile and run DOOM on it, I guarantee it

[@eness379]

why doom

[@GameCyborgCh]

@@eness379 because the doom source code is available to the public and there are nutcases who port it to anything including a toaster

[@eness379]

@@GameCyborgCh i thought it was because it takes a long time to compile it

[@GameCyborgCh]

@@eness379 a 27 year old game won't take long to compile

[@yashagarwal8249]

Yes, i saw one recently made to run on a pregnancy test (yes the kind that is peed on)

[@JulianBabad]

This video just got you a new subscriber. Excellent

[@thetuxguy5438]

I have no idea why I like to watch these types of videos but I like them

[@kadincool]

We could send back-and-forth dead memes on lots of lines lots of times per second so the evesdropper is more likely to find dead memes instead of private information 😂

[@chingmuikwok5377]

did you guys see the"F yeah"?

[@YagoDorea]

Best explanation of RSA I've ever seen.

[@nwoDekaTsyawlA]

Kudos for making a very informative and interesting video about this topic.

[@bernhardtrian7471]

15:24 hahahaha "in that moment he knew , he f@'*ed up " .... everything for nothing

[@elrymemakecontent2610]

me write a scramble on my test paper my teacher : tf is this? me : this answer has been encryption

[@siddharthsinghchauhan8664]

the best video ... the explanation is apt .. precise and thorough... thank u

[@piglauhk1]

Study for years , first time for me to understand what does private key and public key works. Thanks

[@madcat789]

I can't wait to be shitposting on my Dell Quantum XP100K.

[@mickeydee9069]

*Q U A N T U M SHITPOSTING*

[@circumplex9552]

There are gonna be so many memes about this exact thing when quantum computers become mainstream

[@Yamyatos]

It was nicely animated and explained. Sadly i didnt learn anything new in the first 7 or so minutes. Second half was totally awesome in both regards tho :) But, isnt this actually a huge problem? In reality, quantum computers would arrive before we have proper ways to protect ourselves against them, wouldnt they? Because they can be used to decrypt in our current system, but in order to protect us against these attacks, we need a quantum "internet", dont we? So, wouldnt it take years to build the infrastructure needed to protect us against spying quantum computers?

[@frameofessence]

That's why we need Post-Quantum Cryptography, so we can be protected from quantum computers on existing infrastructure.

[@Yamyatos]

But isnt there a huge problem with post-quantum cryptography? If i understood this correctly, for post-quantum cryptography we need to send qubits, which is not possible on our current infrastructure (which is designed for electricity, thus bits). On the other hand, a quantum computer is all you need to break current encryptions. Doesnt that mean that, as soon as the first general purpose quantum computer is build, we are not able to guarantee the security of our messages anymore, while the "solution" to this problems might take years or decades to arrive? Building new infrastructure is no joke. It wont happen over the night. And we will probably only start building it as a reaction to the new threat, which would be way to late. Am i missing something?

[@frameofessence]

You're thinking of "Quantum Cryptography", which is cryptography using qubits. "Post-Quantum Cryptography" is cryptography that works on existing infrastructure that quantum computers can't break, like the ones in 7:06 . ...which is kind of weird since it means that Post-Quantum will probably get implemented before Quantum?

[@SeriousGamingSteam]

Frame of Essence w8 w8 w8, but what about our computers themselves? They cant use quantum cryptography can they? Because if they can, then what the fuck are we so afraid for? And if they can't, don't that mean they can (obviously, but this needs to be said) also not do post-quantum cryptoghrapy?

[@SeriousGamingSteam]

Frame of Essence w8, now that I read your comment again, I guess that's kinda what you said. Right? And if not, then what do you think about it?

[@RandomNullpointer]

love the graphics. many thanks to your efforts

[@epichaxer2265]

Damnnn Sonn i never imagined my brain would ever comprehend let alone understand that stuff...Thank u sooo much

[@phizzhead53]

actually you can send polarised light over a fiber optic conection which would work as a qbit

[@christoffer4862]

Phizzhead This is true, however the polarization of light can be measured exactly and retransmitted. The security implication is a vulnerability to eavesdropping. You can't use polarized light, some other type of qubit must be used for security applications.

[@qwerty687687]

You can use polarized light, you just need two distinct ways to measure it. You can use horizontal and diagonal, if the light comes through, it's a one, if it's blocked it's a zero. If you used diagonal and the other person measures horizontally, the photon will randomly come through or not. Send a photon, have the receiver guess in which direction to measure it and compare it to the direction you originally used, just as it's described in the video.

[@christoffer4862]

qwerty687687 But an eavesdroppper can measure the exact polarization of the light and then retransmit an identical pulse. There's no issue in using a semi-polarized detector.

[@qwerty687687]

No he can't. The sender either polarizes the light "upright" (horizontally or vertically) or diagonally (top left to bottom right or top right to bottom left). So you as the receiver set up your polarization filter horizontally. If the light has been polarized in the horizontal direction, you always measure a photon coming through, that's a one. If the photon was polarized vertically, you always measure no photon coming through, that's a zero. If the photon was polarized along one of the two diagonal directions, you have a 50% chance to get either a one or a zero. Or you set up your filter in one of the diagonal directions, then the same thing applies. You don't know in which of the two systems (straight or diagonal) the light was originally polarized, so you have to guess. After measuring, you can compare your filter settings with the sender, so the photons where both of you used the same setting can be used for encryption. The important part is, when you measure horizontally polarized light in a diagonal direction, it will change its polarity to the direction you measure it in, when it's then measured again horizontally, you get the same result as if the light has always been polarized diagonally, namely a 50% chance of zero or one. When an eavesdropper interferes, he also has to guess which filter setting to use. When he uses a wrong setting where you used the right one, there is a 50% chance that his measurement gives him a different result than the sender intended. Additionally, he forces the polarization that he measured onto the photon, so that you have a n additional 50% chance to measure a wrong polarization, even though your filter setting were correct, so that you cannot decrypt the message. This way, you can not only keep the eavesdropper out, you also know that there is an eavesdropper at all.

[@christoffer4862]

qwerty687687 I think it is possible to develop a polarization filter that is linearly/radially/angularly differently polarized along its plane. But as you say, that would not compromize single photons. But if a light pulse in practice would signal a Qubit, then I think it is possible to eavesdrop.

[@augustinius6586]

How do you send qubits?

[@frameofessence]

+August Inius Send particles of light through a fibre optic cable that preserves polarization

[@ProFow]

Frame of Essence What about WiFi, does air preserve polarization? Also will we stay in the 2.4 GHz and 5 GHz band or does it only work with visible light?

[@Shadow77999]

Combat Arms Fownage we are gonna need disco balls

[@najgauner]

by sending 20 BTC on this bitcoin address: 23568853119

[@Cd5ssmffan]

najgauner send me 50 qubitcoins instead

[@arpanmajumder655]

Enjoyed the whole video and the knowledge associated with it!

[@Reneator]

Really good explanation. Really good video. Got a new subscriber!

[@georgeelsham]

I expect this from 500k+ subs channel

[@bonelesscommunism4031]

Okay so can it run games like hella fast or..?

[@theramendutchman]

Well games have to be specifically compiled (as always) for qubits, but they also need to be coded differently and whole different kinds of code libraries and frameworks are neccesary. So right now? No. In the future? We'll laugh at the consoles 'still' using 128-normal-bit architecture!

[@MariusIsaras]

Best video about quantum computers I have ever seen.

[@nilsb.4199]

I was happy to finally understand regular encryption... Now I have a long way to go before understanding quantum encryption

[@Itsmebsg]

How would quantum computing affect bitcoin mining???

[@britannio]

Rigged Astro you just get lots of bitcoin until everyone has one

[@manu144x]

You can guess the password for any private address and start transfering them. The public key is the address and the private key is the password. It makes the entire bitcoin network useless within seconds.

[@endintiers]

With a quantum mining algorithm you could corner the market (except for other people doing the same). Non-quantum mining would become uneconomic. If someone controls more than I think 40% of the mining they can break/cheat the system. The big problem is that the PPK pairs used to prove identity can be broken so you can't safely send/receive coins. Without quantum encryption Bitcoin (and other value exchange) exchange dies.

[@Shadow77999]

Emanuel Gug so bitcoin will finally crash but, thx to quantum computing, not something else, interesting

[@con_boy]

It immediately invalidates their value

[@romand271]

well the question hasn't been answered yet what is the meaning of life after all?

[@DarkSideSixOfficial]

To live and be love. But more specifically, to do so while progressing mankind and protecting the planet and living things that's made our existence possible.

[@computronium8]

We're not ones and zeros as people usually said, we are qubits and everyday we're discovering and measuring ourselves. The journey itself is the meaning of life

[@starcubey]

...or to follow God and be a disciple instead of following your sinful desires, but you don't have to agree with any of the responses to this comment because it is based on religion (except for 42 because it is the definitive answer).

[@Inertia888]

x=42

[@trispectre8366]

^^

[@peschebichsu]

6:58 would be nice to have a video about these topics and also generaly an update on how thing developed in the last yesrs. Great video though!

[@noxultionis3851]

This was a fantastic video. Wow that explanation was clean.

[@peterstiles1]

12:35 "...hopefully the eavesdropper will respect your privacy..." BWAHAHAHA...the NSA and the 5 eyes...HAHA...respect your privacy...HAHAHA! : (

[@Bulbophile]

Benign listening in isn't the security threat; but is there such a thing as benign eavesdropping? By its nature, it's an intrusion on privacy with mal intent. From governmental sides; corporate; or personal, listening in gives the undue right to sway, steal, and hurt respectively. For eg sake only, of course. Did anyone ever hear anybody say they're going to interfere with xyz's communications to help them? Maybe only in the arena of my enemies' enemy is my friend.

[@nicklaich]

TLDR: unless we have quantum network, we are doomed. haha.

[@mohanj9943]

Excellent bro...You are awesome and your hard work makes you success.

[@MrSonny6155]

When a random video on KZbin discussing a random topic explains public and private keys better than your computer science teacher or textbook. And that segment is literally the introduction. I could have used that explanation half a year ago, because some teachers don't really teach to well.

[@pauloborgmann]

Would you become filthy rich if you mined crypto currency with a quantum computer?

[@LegendBegins]

Modern? Probably not. Future? Maybe! Also maybe not. "It depends" is the best answer anyone can give you.

[@vanguardas9927]

will bitcoin be hacked by a quantum computer is the real question

[@BiggySeth]

Vanguardas Vucava exactly

[@snrd]

Please give me a Patreon page or something where I can donate.

[@silence439]

I agree with you. This person is awesome

[@doctoroctopi5687]

why does this channel not have more subs this is some quality content

[@osamazaid25]

Wow! one of the best video's I have ever seen about encryption.