Multiple recipients (CC and BCC)

We allow multiple recipients on a message.

We deal with this by generating multiple header files, each the same catalog encryption key, but encrypted with the recipients key. A message send to 10 users, will thus have 10 header files, 1 catalog file and 1 or more block and attachment files.

However, there are multiple ways to deal with multiple recipients:

• add them all to the meta-data in the catalog. Allowing recipients to view the list of all recipients (CC)
• don't add them to the meta-data. This makes that recipients cannot view the list of all recipients (BCC). It means that there is no reply-all functionality in that case.