An RPMSG file is an encrypted email message created with email client applications Microsoft Outlook, Microsoft’s email and calendar application. It is sent as a separate attachment to standard email messages and can only be opened by certain users. This restricts access of these files to other users whom are not destined to receive the information in these files. Generally these files are sent with filename message.rpmsg and can be downloaded as well from email, but will not work in this case.
RPMSG File Format
RPMSG files are saved to disc in binary file format. However, its file format specifications are not available publicly for developer’s reference due to encryption.