2-Step Verification

[githuberyt]

I suggest adding 2-Step Verification for matrix accounts to protect users accounts if they used a malicious server or if the admin is snooping on the user's data

[clokep]

This needs to be specified before Synapse adds support for this, see matrix-org/matrix-spec-proposals#1998.

Note that this wouldn't actually help from using a malicious server though.