Name: lot-code-request
Type: request
Purpose: >
  Requests an event lot code deposited for the sender of the message
Response: lot-code
Inherits: message
Elements:
  Signature: { required: true }
  From: { required: true }
  Event-Id: { type: identifier, class: event }
Notes:
  The Lot-Code must be encrypted using the Participant-Id's public
  key. Note that the element's name must not have a tilde at the end,
  because its contents are not meant to be decrypted by the receiving
  server.
Rejection-Codes:
  41: Event does not exist
  42: No lot code deposited for sender