Vetting users (certify/revoke keys)
The public key of the user, stored within the database, gets updated by a valid certification of that user by someone else.
Account Management (public key or fernet symetric)
Recovering account details involves using the private key on client-side JS, without it, the account shouldn't be recoverable.
Jurisdiction Administration (Threshold keys)
Unlocking jurisdiction options requires consent from all the parties sharing a common secret (technically blockchain threshold sigs, not Secure Secret Sharing, unless I can find an uncompromising method).
Voting and elections (Shuffle-Sum)
Elections contain both a publicly signed poll ranking, and a private shuffle-sum operation. The poll is attached to the user's profile, while the Shuffle-Sum operation is used to verify their actual private vote.