The method for the transmission of media data from a multicast service by a first apparatus to a plurality of second apparatuses is suitable for preventing reception of the media data by an unauthorized second apparatus using a security process. A first apparatus is provided which can be used to provide the media data protected by a security process. A third apparatus is provided which can be used to perform the security process with the first apparatus, performance of the security process between the first apparatus and the third apparatus and, on the basis of this, interchange of at least security data between the first apparatus and the third apparatus in order to provide the media data. A second apparatus is selected which can be used to perform at least one reception process for receiving the media data. A first data transmission link is selected which can be used to couple the first apparatus and the second apparatus at least for the purpose of transmitting the media data. The provided media data is received using the second apparatus via the first data transmission link.