Because calendaring and scheduling information is very privacy- sensitive, the protocol used for the transmission of calendaring and scheduling information should have capabilities to protect the information from possible threats, such as eavesdropping, replay, message insertion, deletion, modification, and man-in-the-middle attacks.
As this document only defines the data format and media type of text/ calendar that is independent of any calendar service or protocol, it is up to the actual protocol specifications such as iTIP [2446bis], iMIP [2447bis], and "Calendaring Extensions to WebDAV (CalDAV)" [RFC4791] to describe the threats that the above attacks present, as well as ways in which to mitigate them.