Ticket request

A user requests a ticket for access to certain participants and columns. They either specify a list of subject groups or polymorphic pseudonyms. The servers will translate the PPs and return encrypted local pseudonyms for servers and the user in the ticket. The ticket can be presented to e.g. the Storage Facility later on.

sequenceDiagram
  title Ticket request
  actor User
  participant AM as Access Manager
  participant TS as Transcryptor

  User->>+AM: Subject groups or PPs, columns,<br/>signature + log signature

    %% Space to prevent parsing error in GitLab
    AM-->>AM: #32;
    note right of AM: Check signature
    note right of AM: Check column access
    opt Request with subject groups
      note right of AM: Check subject group access
      note right of AM: Retrieve PPs from DB
      note right of AM: Re-randomize PPs
    end
    note right of AM: RSK with proof on PPs for AM, SF, TS, user

    AM->>+TS: User request with only log signature#59;<br/>PPs, partial pseudonyms, proofs

      TS-->>TS: #32;
      note right of TS: Check log signature
      note right of TS: Check RSK proofs for AM, SF, TS from PP
      note right of TS: Finish RSK for AM, SF, TS, user
      note right of TS: Log: user request with only log signature#59;<br/>TS pseudonyms#59; access modes#59;<br/>hash of PPs & translated AM, SF, user pseudonyms

    TS->>-AM: PPs & translated AM, SF, user pseudonyms#59; log ID

    AM-->>AM: #32;
    note right of AM: Check participant access<br/>(using decrypted AM pseudonyms)
    opt Write request with PPs
      note right of AM: Add PPs for LPs to DB
    end
    note right of AM: Create ticket signed by AM with<br/>timestamp#59; access modes#59; columns#59; user group#59;<br/>PPs & translated AM, SF, user pseudonyms

    AM->>+TS: Ticket signed by AM, log ID

      TS-->>TS: #32;
      note right of TS: Check signature
      note right of TS: Log: log ID, columns, timestamp
      note right of TS: Sign ticket

    TS->>-AM: TS ticket signature

    AM-->>AM: #32;
    note right of AM: Add TS signature to ticket

  AM->>-User: Ticket signed by AM & TS