How Messaging Layer Security Works (sort of*)
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How Messaging Layer Security Works (sort of*)
Hubert Chathi
1
Title
Warning
Why MLS
Trees
Trees (cont'd)
fine print
Tree nodes contain
Alice creates a group
Alice invites bob and Carol - full
Alice invites Bob and Carol
Cryptographic Ratchet
Alice sends to Bob
Bob decrypts the tree
Alice sends to Carol
Alice invites bob and Carol - full
Alice sends a message
Alice "removes" Bob
Carol invites Dan, Erin, and Frank
Carol invites Dan, Erin, and Frank
Carol sends to the group
Alice decrypts
Alice decrypts
Carol sends to Dan
Dan derives K3''
Carol sends to Erin
Carol sends to Frank
Carol sends to Frank
Dan updates the group secret
Alice can decrypt K4
Carol and Erin can decrypt K4'
Frank can decrypt K4''
Dan updates group secret - full
Overview