{
  "version": 1,
  "kind": "sequence",
  "title": "Signing in with a one-time code",
  "description": "A person signs in; the code goes out by text message without the server waiting for it, and the audit log is told without anyone waiting either.",
  "participants": [
    {"id": "user", "text": "Account holder", "role": "actor"},
    {"id": "app", "text": "Web app"},
    {"id": "auth", "text": "Sign-in service", "role": "emphasis"},
    {"id": "sms", "text": "Text gateway", "role": "note"},
    {"id": "audit", "text": "Audit log"}
  ],
  "messages": [
    {"from": "user", "to": "app", "text": "email and password"},
    {"from": "app", "to": "auth", "text": "check password"},
    {"from": "auth", "to": "sms", "text": "send code 482 913", "role": "async"},
    {"from": "auth", "to": "app", "text": "code required", "role": "weak"},
    {"from": "app", "to": "user", "text": "enter the code", "role": "weak"},
    {"from": "sms", "to": "user", "text": "text message", "role": "async"},
    {"from": "user", "to": "app", "text": "482 913"},
    {"from": "app", "to": "auth", "text": "verify code"},
    {"from": "auth", "to": "audit", "text": "signed in", "role": "async"},
    {"from": "auth", "to": "app", "text": "session token", "role": "weak"},
    {"from": "app", "to": "user", "text": "home page", "role": "weak"}
  ]
}