Messaging layer security: Encrypting a group chat

[@oncedidactic]

So easy to understand the concepts and see deeper into the space of problems and solutions. Awesome!! Thanks!

[@Der_Stille_Zuschauer]

00:00 - Introduction and the Challenge 00:54 - some Ideas how to solve it 00:54 - Parallelized Conversation 01:40 - Key Systems 02:17 - Messaging Layer Security (MLS) (Tree System) 03:37 - Key System 05:00 - Key Schedule 06:50 - Root Key change 09:53 - Remove Group Member 11:13 - Conclusion

[@ericdanielski4802]

This comment should be pinned at the top.

[@fusionsid]

Thank you for this and the other video, Im currently making a chat app and couldnt find any good videos explaining group encryption

[@hashtag9990]

hey gentleman, would you like to share your wisdom? we want to implement encryption in our app too, and we are not knowledgeable enough, ofcourse you don't have to share your wisdom for nothing.

[@eapiii]

Great set of videos

[@rhoumarhouma9714]

brilliant and smooth presenration tghank you

[@charleskhenry]

Amazing.

[@devobern]

Great explanation of MLS! I have a question about how a single message is encrypted in the protocol: Is the same message encryption key used by all group members during an epoch, or does each sender derive their own encryption key (e.g., from the root secret or another source)? Could you clarify how message keys are derived and managed for individual senders?

[@tonpa]

Perfection!

[@guzh]

It is unclear how F gets its private key at 6'16''. It is also unclear why the rachet can go up the tree as well as down the tree.

[@sojn4]

It’s a bit confusing in the graphics but F must derive its own Public Private key pairs itself first, give Alice the public key, then Alice will wrap the group secrets (tree private keys) with Franks public key so that F can join the group chat. F gets its welcome message directly from Alice. Basically you can use any method to give F the welcome message.

[@sojn4]

Also think of the ratchet as the “propagation path” for a new key. The ratchet doesn’t HAVE to go unidirectional on the tree. The ratchet is in the direction of any new key that’s being propagated.

[@alexipeck4201]

I have never heard the word epoch pronounced as you did. It sounds like you are saying "epic"

[@markcuello5]

HELP

[@leesweets4110]

Epic? Quit saying epic. Its clearly the other pronunciation. Because your way of doing it is ambiguous with another word.

[@PrecariousPosition]

I've never heard it aloud that way. How bizarre. I wouldn't have thought it was a controversial word

[@StevenAkinyemi]

Ikr. If pronouncing it as epic is ambigous, why not save us the confusion?

[@erikb3799]

I've heard ep-awk, ep-uck, and ee-pawk. It seems like she doesn't like ee-pawk, but there are other pronunciations that are less confusing than ep-ick.

[@mooseyard]

There’s nothing wrong with homonyms; English is full of them. And English is full of words with multiple valid pronunciations. Arguing about the “right” pronunciation is pointless.

[@beeble2003]

@@PrecariousPosition It's only controversial to her because she mispronounces it, so people argue with her about it! The two accepted pronunciations are EE-pock and EPP@k, where I'm writing "@" for schwa, as in the second vowel of "lemon".