Update matrix

protocols/matrix.md

@@ -10,7 +10,7 @@ A Matrix [identifier](https://matrix.org/docs/spec/appendices#common-identifier-
 
 Other sigil IDs include "!" for Room ID, "$" for Event ID, "+" for Group ID, and "#" for room alias.
 
-User accounts, once created on a homeserver, cannot be migrated. To change servers, a user must make a new account. [Automated tooling](https://modular.im/tools/matrix-migration) exists to help with inviting the new account into rooms the previous account was in.
+User accounts, once created on a homeserver, cannot be migrated. To change servers, a user must make a new account. [Automated tooling](https://modular.im/tools/matrix-migration) exists to help with inviting the new account into rooms the previous account was in. There are eventual plans to switch to user keys which will enable [portable identities](https://gist.github.com/neilalexander/90cf1fa6980ade4b3385ebf536f634fe). A Matrix account could also [map to a DID](https://github.com/friedger/matrix-doc/blob/3pid_did_association/proposals/1781-3pid-did-association.md).
 
 Users have a Matrix user ID, but can also use [3rd party IDs (3PIDs)](https://matrix.org/docs/spec/appendices#pid-types). Matrix identity servers map 3rd party IDs such as email addresses and phone numbers to Matrix ids. The use of this service is optional. A globally federated cluster of trusted identity servers verify and replicate the mappings, although this is considered a stopgap solution until a fully decentralized identity solution is adopted.
 
@@ -26,7 +26,7 @@ In the federated version of Matrix, all messages are currently sent out full-mes
 
 #### P2p
 
-Matrix has released a p2p version that runs client-side. P2p Matrix avoids the problem of homeservers accumulating metadata, and simplifies signup by not requiring new users to pick a homeserver. The new p2p implementation runs the homeserver on the client. The p2p network is currently separate from the federated network, but the end goal is to connect the two in a hybrid federated/p2p model. Network transports being considered for p2p Matrix include libp2p, Yggdrasil, or hyperswarm.
+Matrix has released a p2p version that runs client-side. P2p Matrix avoids the problem of homeservers accumulating metadata, and simplifies signup by not requiring new users to pick a homeserver. The new p2p implementation runs the homeserver on the client. The p2p network is currently separate from the federated network, but the end goal is to connect the two in a hybrid federated/p2p model. Network transports being considered for p2p Matrix include libp2p, Yggdrasil, or hyperswarm. In p2p Matrix, the hostname of the user is its libp2p or yggdrasil public key.
 
 https://matrix.org/blog/2020/06/02/introducing-p-2-p-matrix
 
@@ -55,7 +55,7 @@ Features supporting more advanced social functionality are being developed, such
 
 Matrix homeservers have access to metadata about conversations, because the homeservers of all users in a given conversation have to store that conversation's metadata. P2p Matrix mitigates this privacy issue.
 
-Matrix recently introduced end-to-end encryption by default for private messages. This was on the roadmap since the beginning, because conversations are replicated over every server participating in a room, and there is no guarantee against servers looking into conversations.
+Matrix recently introduced end-to-end encryption by default for private messages. This was on the roadmap since the beginning, because conversations are replicated over every server participating in a room, and there is no guarantee against servers looking into conversations. For Matrix E2E encryption, each device has its own identity key, and per-user keys are gossipped between devices when the user logs in.
 
 [olm e2e encryption](https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-encryption-security-assessment-released-and-implemented-cross-platform-on-riot-at-last)
 [encryption for private messages](https://matrix.org/blog/2020/05/06/cross-signing-and-end-to-end-encryption-by-default-is-here)
@@ -80,10 +80,12 @@ The majority of traffic is currently instant messaging.
 
 ### Scalability & Metrics
 
-Scalability study: https://arxiv.org/pdf/1910.06295.pdf
+Matrix “rooms” replicate message content across all participating servers, but lazily-replicates file content. A server only retrieves a file if a user on that server requests it.
 
 The public network currently (Feb 2020) has 17.9M known addressable users (as of June 2020), with more in private federations or on servers which don't report stats. 30% of publicly visible users are on the matrix.org homeserver. There are many smaller servers as well.
 
+Scalability study: https://arxiv.org/pdf/1910.06295.pdf
+
 There are over 1,500 active developers in the community.
 
 ### Links