"The program uses the Real-Time Messaging Protocol (RTMP) to
record not only streamed Flash media but also encrypted streams.
Adobe added encryption to its proprietary protocol on introducing
Flash Media Server 3 in order to prevent the recording of Flash
content, and defined RTMPE (RMTP encrypted) for the purpose. Adobe
takes the view that its copy protection can be circumvented by the
RTMPE support incorporated in rtmpdump and, in its cease-and-desist
notice, invokes the [Digital Millennium Copyright Act to prevent
the distribution of the software."