It's scary to think about how one day Alice or Bob may die and then all communication protocols will need to be reworked...
@AV14615 жыл бұрын
Well.. When Eve dies we won't need cryptography anyway.
@autohmae5 жыл бұрын
@@AV1461 Let's not forget Mallory .
@shaggydawg54193 жыл бұрын
what's scary is the fact he still has that ancient paper that was used in a mainframe printer.
@Aemilindore3 жыл бұрын
Uneducated people like this mention that WhatsApp is end to end. That has a huge impact on the community.
@tommykarrick91303 жыл бұрын
Maybe the real Alice and Bob were the friends we made along the way
@fablungo5 жыл бұрын
For the avoidance of doubt, Facebook messenger does not use this (or any form of end-to-end encryption) in normal messenger conversations; it is only used when you start a "Secret Conversation".
@hybby5 жыл бұрын
And secret conversations are locked to 1 device, I believe. Can't confirm; haven't used FB in awhile.
@juggernaut935 жыл бұрын
hybby yes, only one device
@tabaks5 жыл бұрын
There ARE people who use Facebook?
@OpisCossack5 жыл бұрын
send am image hosted on a private server to a friend, using Skype, Facebook Messenger, etc. You'll notice most of them access it under the guise of providing a preview in the client.
@michalveselenyi38014 жыл бұрын
there is no secret when dealing with facebook, never was :D
@justhungry675 жыл бұрын
*All the encryption processes* Bob to Alice: "Sup?"
@KylePiira5 жыл бұрын
*Another set of encryption processes* Alice to Bob: "Not much. Just ate."
@kagayakuangel58283 жыл бұрын
In my paper I am not using Alice and Bob lol. I will use Anna, Ben and Eric or something lool
@MukeshPatel-ei3we3 жыл бұрын
So finally it’s recommended by KZbin 🙂
@dionnigamingandmusicgaming38743 жыл бұрын
Recommended after 2 years
@NuggetsNews5 жыл бұрын
Man I love these videos. Learn so much! Thank you
@pooounderscoreman5 жыл бұрын
Nugget's News brushing up on your cryptography?
@revanjagergaming87145 жыл бұрын
I had no idea that instant messaging was so complicated, learn something new every day. Thanks for taking the time to educate us pleb's. :D
@forlornskies65334 жыл бұрын
“Safe and Secure” messaging is complicated....behind the scenes.
@VivekYadav-ds8oz3 жыл бұрын
It's complicated if your messaging app actually follows through.
@basfarissah80044 ай бұрын
I used to teach my students via WhatsApp, but we've now fully switched to the SIGNAL messaging app and are having a great experience.❤️🌹
@addubgib5 жыл бұрын
I see Dr. Pound, I click.
@code-dredd5 жыл бұрын
I thought you'd say "I pound [that link]", but I was disappointed.
@0LoneTech5 жыл бұрын
Signal's safety number isn't one hash of both keys; it's a hash of each key, so a pair of fingerprints, sorted so it looks the same on both screens. One half is always your fingerprint.
@RajParekh075 жыл бұрын
Dr. Mike Pound is the best in explaining!
@hugowoesthuis5 жыл бұрын
Finally some attention for Signal and OWS!
@omarelkhatib1503 жыл бұрын
what abou attention now 2021 after whatsapp TOS update.
@fobudomh3 жыл бұрын
I only found out about it after Elon Musk tweeted. Google Play would never show this app earlier. You had to manually search for it.
@ebrahimalfardan88233 жыл бұрын
Dr Mike has a perfect record of putting me and my trivial skills in my place. He definitely got me after the first two public keys.
@domtorque5 жыл бұрын
Zucc disapproves.
@d1oftwins5 жыл бұрын
Well that Zuccs...not!
@Anton-cv2ti3 жыл бұрын
That's generally a sign you're doing it right
@saneyarkhazin76713 жыл бұрын
This aged well
@swapnilgohil72803 жыл бұрын
@@saneyarkhazin7671 always has been
@kevinhu8360Ай бұрын
@@saneyarkhazin7671 messenger's end to end is a joke compared to signals. they still store all their keys on the meta servers so the point of the encryption is basically moot for user privacy
@zelllers5 жыл бұрын
Excellent, I was hoping you'd cover the ratchet mechanisms built into the protocol, but I see they're coming in the next video. Thank you for spreading awareness!
@blk_lies5 жыл бұрын
It's time that this guy takes over the channel
@ewenchan12392 жыл бұрын
I LOVE how Dr. Pound explains stuff in lay people terms.
@tasoftworks5 жыл бұрын
Why is it called triple Diffie-Hellman if it uses four Diffie-Hellmans?
@_PsychoFish_5 жыл бұрын
Signal
@mare46025 жыл бұрын
i have a question: what happens in group messaging? like in whatsapp groups? if everyone is end-to-end encryped with everyone how can i read what happens between 2 group members?
@ΕρμήςΔούλος5 жыл бұрын
As far as I know, in my own words, you include all the public keys of your friends in the encrypted message so that it can be opened by them. As i see it, the more people your message is directed to,the more vulnerable it is.
@PinakiGupta82Appu5 жыл бұрын
@@ΕρμήςΔούλος absolutely!
@jimsstek55674 жыл бұрын
Guys Frankly Telling You I have been using Signal Private messenger for almost One years , its Really working Awesome , Finally I I found my personal data privacy and security with Signal private messenger Thanks to Signal team, they made privacy easy
@hampelmann58044 жыл бұрын
@@jimsstek5567 man you got paid for this? Whatsapp also uses e2e encryption confirmed by OWS, so who cares about alternatives
@TheTranceViruz4 жыл бұрын
@@hampelmann5804 why not? Signal messenger developer are the same team that develop signal protocol.
@praveenb90485 жыл бұрын
So there's only a finite amount of backlog messages that the server can receive for me when I'm offline, since there's a finite number of one-time keys that it has for me?
@autohmae5 жыл бұрын
Yes, that is correct. Whatsapp and Signal use the open source libsignal library developed by Wisper Systems, at first glance it looks to me like the documentation on how to use libsignal suggests to create a 100 pre-keys.
@SnoopyDoofie2 жыл бұрын
I'm pretty sure those one-time keys are only used for setting up the communication. You don't need a new key for every message sent. I could be wrong, but that is my understanding from this video.
@J33d335 жыл бұрын
Very informative! Didn't knew end-to-end is so complicated!
@auto_ego5 жыл бұрын
Everywhere I go, Alice and Bob have been there first.
@swagfogg3 жыл бұрын
Anyone after new terms of WhatsApp?
@kwadwoamponsah3 жыл бұрын
Yep today's moving day 😄
@b.e.82073 жыл бұрын
@@kwadwoamponsah F1ck whatsapp
@dhuvsgg75535 жыл бұрын
what about group chats? How are encryption keys generated in a group chat. What happens when you add a member or remove a member from the group. Does the whole key change? This would make a very informative video
@derekkonigsberg20475 жыл бұрын
Thanks for making this video. I'm always looking for better ways to try and explain the Signal Protocol to other people, and this makes an excellent starting point. I've personally focused so much on the ratcheting process (hopefully to be covered well in the next video) that I've almost forgotten about the nuances of the session setup process.
@voltagedrop5 жыл бұрын
I saw a guy do a Triple Diffie Helman at the Coney Island pier years ago...
@tabaks5 жыл бұрын
Please, do tell!
@ASBlueful5 жыл бұрын
@@tabaks Oh! Did you see a gu (black hoodie, very sad look) sitting on the edge of the pier, throwing himself into the sea, while talking to an imaginary friend?
@tomormiston65925 жыл бұрын
I'm feeling very thick after listening to this...
@Not.Your.Business5 жыл бұрын
the two dislikes are from some men in the middle
@fahimp35 жыл бұрын
u r wrong there r 12 of them now!
@Not.Your.Business5 жыл бұрын
@Fahim Saharaiar, what can I say?!... other than I spoke too soon...
@ciarfah5 жыл бұрын
Andrei Macaria u rong the r 18 of the now!!!¡
@martinrocket14365 жыл бұрын
Andrei Macaria, one of them being Mark Zuckerberg
@fahimp35 жыл бұрын
@@Not.Your.Business How about this there are "dislike-number number of dislikes!" Ha, can't prove me wrong now!
@pritishpatil93513 жыл бұрын
Who else is watching this in 2021? suddenly super relevant!
@bartholomewtott38122 жыл бұрын
I think the only people who follow this guy already know the subject.
@aurimasb17325 жыл бұрын
Signal needs to be more popular, I hate using messenger, sms to communicate with friends.
@f1refly13375 жыл бұрын
so make it more popular?
@luziferkupfer5 жыл бұрын
Pretty easy thing to say, hard thing to accomplish. It was somewhat of a battle to have the majority of my family to install Signal (they still only use it to communicate with me, otherwise they use WhatsApp) convincing friends was/is nearly impossible. After the last Facebook scandal some of them installed Signal, but still only fraction.
@goat52494 жыл бұрын
Dr. Pound. What a name.
@Stillshot102004 жыл бұрын
Awesome video. Would appreciate one on the KDF.
@nicolaiveliki14093 жыл бұрын
Usually you will be prompted forced to use a different means of identification, typically your cell number, when you register, and the app will verify this by sending you a message via your mobile network. This is also an out of band identity verification. It is somewhat compromised by burner phones which are now also (cheap) smart phones...
@RemyDrijkoningen3 жыл бұрын
The protocol has been extended to support "multi-device" on whatsapp, it might be super interresting to learn how that changes the game, how it is still possible to verify each other ver-changing bundle of devices on each end of the line and what prevents new rogue devices to be forefully "added" to people bundle, as well as how to device enrollement is secured.
@FrozenBusChannel Жыл бұрын
and multi-device on Signal itself too! It's amazing how messages can securely sync between my phone and PC
@amitojha54644 жыл бұрын
Hi amit from india active user of Signal Private Messenger. The messenger is awesome because it offers me full control over my messages. The best part is that it has a lot of advanced features like 'disappearing messages', 'screen lock', 'incognito keyboard', 'read receipts', 'message trimming' etc.
@stanislavstankov51608 ай бұрын
Thanks for sharing this amazing explanation!
@TheVergile5 жыл бұрын
Shouldn't it be possible to do key exchange for a new contact with a one-time message over the phone network, skipping the privately owned server? Then you could verify each other based on the phone number.
@silkworm68615 жыл бұрын
The Matrix protocol (and the Riot messenger) is my choice!
@pm790805 жыл бұрын
@Ellaine It does bridging. If you want to look witty at least look at their website.
@pm790805 жыл бұрын
@@no-defun-allowed Federation is a form of distribution. Do you mean peer-to-peer?
If Android and iOS are keylogging or the application installed is doing keylogging it does not matter if the data is encrypted when transferred out of your phone because at the side you clear text is encrypted and sent to the total surveillance network...
@fetchstixRHD5 жыл бұрын
That was actually mentioned in their End to End Encrytion video: something along the lines of "end to end encrytion is secure enough that attacking the endpoints is easier/it doesn't prevent someone from taking your phone and reading your messages".
@bradbeattie5 жыл бұрын
Say I install Eve's app. It generates a keypair for me and uses that to encrypt my messages to Bob. Nothing's stopping Eve from just decrpyting my messages. That's the problem with this app-based world. People aren't supplying their own keys. If the app and the servers and the key generators are all owned by the same person, your privacy is fully at the whim of Eve.
@gradientO3 жыл бұрын
Anyone after change in WhatsApp Privacy Policy & everyone switching to Signal and Telegram?
@TOBImue15 жыл бұрын
How does the protocol work for multiple devices? Like Whatsapp Web or the signal desktop app?
@philips90425 жыл бұрын
By scanning the QR code you set up a secure connection between the browser/desktop app and the content of your message is then sent to the app on your phone, from where it is sent as a normal message.
@openalternative3 жыл бұрын
@@philips9042, you can use Signal on Desktop without having your phone turned on.
@praecorloth2 жыл бұрын
One day, the University of Nottingham will run out of dot matrix printer paper, and there will be no more Computerphile videos. And then we'll all be sad. :(
@bilthon5 жыл бұрын
So I assume we would have one pre-key bundle for each conversation, is that right?
@danielf.71515 жыл бұрын
1:52 How does that work? does Bob produce a second public key and encrypt it with the private key from the identity key?
@BlackHermit5 жыл бұрын
Bring forth the true Signal Protocol!
@uzeyirveli5 жыл бұрын
Guys could you do it a video on RSA? It would be interesting to see how it is used in the real world (with real examples), and also I am doing a project on it so it would be really helpful :D
@Xclann5 жыл бұрын
So to ensure IP_kB belongs to Bob, you had to do it out of band, most likely meeting in person. Then, why not just form a shared key, or a sequence of shared keys at that point? I guess the advantage of doing it this way is so that the OP_kB can be updated with more keys without meeting out of band again after the first time...
@petersuvara5 жыл бұрын
I would love to see outtakes of these videos :D
@Lysergesaure15 жыл бұрын
So, ”security codes” are the PGP equivalent of sharing key fingerprints in person. Is there something similar to a web of trust (or a “strong set”) in Signal?
@durnsidh64835 жыл бұрын
Not really. Key transmission is handled by the server.
@Lysergesaure15 жыл бұрын
@@durnsidh6483 Just like PGP and keyservers. People don't exchange their public keys, just the fingerprints. Which are very similar to these codes.
@durnsidh64835 жыл бұрын
@@Lysergesaure1 But people don't sign each others keys, so there is no way to build a web. It's technically possible to sign other people's keys using a somewhat contrived signing algorithm that's used to sign the SPK's, but in terms of the apps functionality, no.
@AnabraHUN2 жыл бұрын
Hey, I got a bit lost around 8:30, where you are talking about how the server combines the two identity keys. I don't quite understand how that helps ruling out man-in-the-middle attacks. Shouldn't we also incorporate the signed versions and and check them? Cheers
@FrozenBusChannel Жыл бұрын
4 years and the next part is still "coming soon"...
@dielfonelletab87115 жыл бұрын
Why not just use Bob's public key to encrypt the messages? To mitigate the problems of private keys being leaked?
@fetchstixRHD5 жыл бұрын
I'm a bit confused by what you're suggesting here?
@JamesJordanson5 жыл бұрын
because (from what I gather) there is no RSA/DSA protocols being used here, just diffie hellman which only create symetric keys.
@fetchstixRHD5 жыл бұрын
graymalkinmendel: That was one possible answer I was thinking, even with RSA you get problems (asymmetric key encryption tends to be more computationally expensive than symmetric) but it’s really ambiguously worded and I’m not sure what they mean by mitigating the risk of leaking private keys...
@tyrannyresponseteam95344 жыл бұрын
I have a great idea for total private communications. I hate to say it here for fear it may get stolen, but I'm going to say it anyway. What if we started a business where we wrote things on paper and took them to a place where a person would deliver it to the person you're reaching out to. We could charge for each paper delivered, kinda like Uber but for papers.🤔
@jeffcaldwell71464 жыл бұрын
Unless you send the courier with an encryption key that will unlock another encryption key that was sent via unsecure chat.
@rajdeepbiswas89123 жыл бұрын
Oh boy this video is gonna blow up now again
@StarlinGrimes5 жыл бұрын
Is this the same concept as secure business communications with public and private keys, and if not how do does one go about learning this thanks.
@joelstephenson80172 жыл бұрын
Have you figured out how to learn it yet?
@vinay__baliyan3 жыл бұрын
Dr. Mike mentioned Signal in 2018, how cool is that?
@hul83762 жыл бұрын
Thanks for the explanation!
@madsmikkel12945 жыл бұрын
We are using MyChat enterprise messenger at the office. It does not require a phone number and can work without the Internet. Perfect for us for now. It also has own server, so... heck no more public messengers :D
@krozaine3 жыл бұрын
I am not sure if "WhatsApp" was there in the video title earlier :\
@Omniback204 жыл бұрын
What's the difference between the safety number and a siganture?
@whitslack5 жыл бұрын
The safety number isn't generated by a hash function. It's actually just the concatenation of a part of each party's identity key fingerprint (lesser part first). You can check this for yourself by comparing your safety numbers from two different conversations. Half of the digit string will be the same in every conversation on your phone. That half corresponds to your identity key.
@Wishwader5 жыл бұрын
Matt Whitlock - To his credit, he did make clear it wasn't literally a hash. The analogy was apt.
@0LoneTech5 жыл бұрын
The fingerprint is literally a hash of a public key, though. What's unclear (deliberately) is that there are two, sorted for consistency.
@whitslack5 жыл бұрын
@@0LoneTech Right. It's the concatenation of two (truncated) hashes, not the hash of a concatenation.
@sahaqhashum3478 ай бұрын
private key and public key both are generated by the app, it mean app knows how to generate the private key and all the terminology, it is possible to break this encryption by that creator who make the app or who have all the control , is that not true generating the keys by the app may be store in the server at that time
@FlaSh3ch5 жыл бұрын
Major key alert 🔑 Ans another one 🔑
@4crafters5978 ай бұрын
So if I understand this correctly if there is a man in the middle, the safety numbers will not match up, and if they do, there is a guarantee that there is no such attack? A man in the middle could also only drop and replay messages, but not read them due to the encryption, correct?
@user-or7ji5hv8y3 жыл бұрын
How do these guys know everything.
@vorosbence3 жыл бұрын
By watching this channel. duh.
@JamesJordanson5 жыл бұрын
Also, does the security number prevent a man in the beggining attack, where somone hijacks the initial handshake with the server?
@maxmayer90284 жыл бұрын
It does not prevent it but the safety number verification will fail if someone did an active man in the middle attack on your initial handshake. For usability reasons Signal and most other end to end encrypted messengers use the trust on first use (tofu) principle. They assume that there was no active man in the middle attack on the initial handshake and even in the case of new handshake which is usually triggered for benign reasons, e.g. a new phone, they just notify you in the conversation view. For highly sensitive conversations you should always verify the safety number out of band before you trust the communications channel.
@recreant3595 жыл бұрын
Oooo sneak preview of the next episode in the end credits
@johnfrancisdoe15635 жыл бұрын
What does the multiple DH do that isn't already achieved by Bob and Alice signing each of his ephemeral public keys and destroying the ephemeral private keys after one use?
@autohmae5 жыл бұрын
I believe it helps to make sure the server is not a man-in-the-middle.
@rabinabaga58626 ай бұрын
how does alice receive the identity key of bob, isnot private key supposed to be kept with him only? @ 3:30
@Newjorciks5 жыл бұрын
It may be safe against other parties doing the MITM attack, but nothing stops the actual service(For example WhatsApp) to do MITM on the messages. The only way to verify is with the "security key", but nothing is stopping WhatsApp from just generating a number, sending it to both phones and displaying that number.
@boriz_5 жыл бұрын
Neat stuff but can we talk about what's happening on that whiteboard? I see a line formula the rest doesn't seem to correlate...
@SouravTechLabs5 жыл бұрын
A question for you: Why can't we just open whatsapp-web and do whatsapp on the computer without an internet connection on the phone?
@JoshUnwin5 жыл бұрын
Because of exactly this, the encryption means the messages must go via your phone, hence the name 'end-to-end'. Your phone is one end, the other persons is the other end.
@openalternative3 жыл бұрын
@@JoshUnwin, but you can use Signal on Desktop without having your phone turned on.
@randomrandom3163 жыл бұрын
Hypothetically speaking, if the client is not open source and installed from source itself and we do not verify the safety number off the band, people controlling Signal could man in the middle attack us if they were so inclined. Thankfully we can install from source and also verify the safety numbers so its not an issue. Again hypothetically speaking Signal servers could be setup such that it only attempts man in the middle attack from Playstore but not the ones installed from source. Please correct me if I have misunderstood the way this works.
@andrewwatts19973 жыл бұрын
A technical explination for how SIMP's work
@bouhannacheabdallah5 жыл бұрын
you've killed my trust on the messaging communications hh
@LoftechUK3 жыл бұрын
Wow. So informative I had to join
@talkshowlivehost34763 жыл бұрын
just answer me one question if the signal is open source then how it can be end-to-end encrypted ???
@esquilax55633 жыл бұрын
The two are unrelated. Open source just means that the code is freely available, but the code doesn't include these encryption keys, it only contains the functions which generate them. It's like the difference between publicly saying "we have a secret password" (making your "code" open source) and actually saying what the password is (giving up your "encryption key")
@MarcelRobitaille5 жыл бұрын
Signal does this key exchange for every message, right? Is it possible to only do the key exchange once or to do it via SMS (no server)? I miss being able to text without data.
@0xkslkdedcs55 жыл бұрын
Via sms? Lol
@MarcelRobitaille5 жыл бұрын
@@0xkslkdedcs5 They keys are just text so you could send them over sms, no?
@autohmae5 жыл бұрын
@@MarcelRobitaille seems some Encrypted SMS apps do exists, but not very popular.
@Schnickalodeon3 жыл бұрын
At 5:53 I didn't got which keys are used to perform Diffie-Helman? for 1: a = IPKA (Private) ? b = SPKB (Private) ? g = IPKA (Public)? n = SPKB (Private)? So the Public Keys from the Pre-Key-Bundle are used as the public variables? Is that the Idea?
@tabaks5 жыл бұрын
And, that's how it came to be that Bob's your uncle and Alice you aunt!
@erikprantare6964 жыл бұрын
Do a video on the matrix protocol!
@climatechangedoesntbargain91404 жыл бұрын
@Computerphile You could explain Matrix (matrix.org)
@Monothefox5 жыл бұрын
How about the new packet protocol from Google that’s about to become a new standard for internet traffic?
@ko-Daegu5 жыл бұрын
Monothefox What protocol would love if you know ... Put a link or say the name of the protocol at least ...
@GitarrenSchlepper5 жыл бұрын
@@ko-Daegu I think he is talking about QUIC
@9emirhan5 жыл бұрын
RCS?
@johan.mp45 жыл бұрын
@@GitarrenSchlepper which now is HTTP/3.
@tabaks5 жыл бұрын
Monothefox, how about more information, less drama?
@martinrocket14365 жыл бұрын
And if you are using whatsapp, your private keys will be forwarded to the NSA. Or will they not? How will we ever know if it is closed source. And that's why cool kids use XMPP with conversations or quicksy.
@KylePiira5 жыл бұрын
Conversations + Gajim ftw. Yay.
@kiryukazama_3 жыл бұрын
you better use whiteboard rather than paper. great explanation
@androkon69203 жыл бұрын
I understand now.
@U014B5 жыл бұрын
What were you working on that necessitated drawing a block of wood on the whiteboard?
@fsxelw5 жыл бұрын
How do we know if the safety number itself is even generated correctly?
@An.Individual3 жыл бұрын
what does this give over simply using OpenPGP?
@blackstarmaster4 жыл бұрын
Whattsapp is using entd-to-end encryption? Moxie Marlinspike also sais they used actually the signal protocol. But how do you know? Whattsapp is not open source so what if the "safety number" is just a phantasy number displayed on both clients (but not related to the actual keys)? Whattsapp can still play the man in the mitle using their proprietary server software? why should i trust this companys PR? is there a proof of what they do (or certainly not do) on the server? they are the generators of the keys. What about the ECDH backdoor used by whattsapp? Is it possible calculate a hash of the running binary and compare it to a self compiled piece of open source code?
@biprajitsarkar983 жыл бұрын
Is it Leonard from Big bang theory?
@anttikalpio45772 жыл бұрын
Can I just call my friend and verify it’s him instead of security keys?
@americanswan5 жыл бұрын
Threema is so 👍 Deimler uses it in house. Try it out.
@TrueNorth19704 жыл бұрын
How does / how do chat clients like "Slack", or the Open Source GitHub project "Mattermost" etc do security ?
@jacsization Жыл бұрын
Does Snapchat use Signal Protocol for their videos and photos??
@LEO-xo9cz5 жыл бұрын
I'm having problems sending files. Tried to send an audio file but it keeps failing.