How Signal Instant Messaging Protocol Works (& WhatsApp etc) - Computerphile

How do instant message apps do end to end encryption when one phone may not even be switched on yet? Dr Mike Pound on the Signal protocol at the core of most messaging apps.

Double Ratchet: COMING SOON!

This video was filmed and edited by Sean Riley.

[wolframstahl]

It's scary to think about how one day Alice or Bob may die and then all communication protocols will need to be reworked...

[justhungry]

*All the encryption processes*

Bob to Alice: "Sup?"

[fablungo]

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".

[NuggetsNews]

Man I love these videos. Learn so much! Thank you

[MukeshPatel-eiwe]

So finally it’s recommended by YouTube 🙂

[basfarissah]

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.❤️🌹

[revanjagergaming]

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

[RajParekh]

Dr. Mike Pound is the best in explaining!

[ebrahimalfardan]

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.

[LoneTech]

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.

[zelllers]

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!

[jouk]

Very informative! Didn't knew end-to-end is so complicated!

[voltagedrop]

I saw a guy do a Triple Diffie Helman at the Coney Island pier years ago...

[hugowoesthuis]

Finally some attention for Signal and OWS!

[ewenchan]

I LOVE how Dr. Pound explains stuff in lay people terms.

[tasoftworks]

Why is it called triple Diffie-Hellman if it uses four Diffie-Hellmans?

[Not.Your.Business]

the two dislikes are from some men in the middle

[praveenb]

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?

[dhuvsgg]

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

[derekkonigsberg]

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.