concept Writing
  references
    Public_Key
    Session

  state
    user_handle: String
    has_key_pair: Boolean
    message: String
    signed_message: String
    proof_of_work_solved: Boolean

  actions
    writeSomething(message: String)
      pre true
      set message to the provided message

    signAsUser()
      pre has_key_pair
      set signed_message to sign(message, selectPrivateKey())

    solvePuzzle()
      pre true
      // Additional logic to solve the proof of work puzzle
      set proof_of_work_solved to true

    sendNow()
      pre true
      // Additional logic to send the message
      // This may involve utilizing the signed message, user handle, etc.

  operational principle
    after writeSomething(message), the message is set
    after signAsUser(), the message is signed using the user's private key
    after solvePuzzle(), the proof of work puzzle is solved
    after sendNow(), the message is sent

  where
    selectPrivateKey(): PrivateKey
      pre has_key_pair
      // Additional logic to select the user's private key