Trannsmision method of information data from a sender to a receiver via a transcoder.

A method of transmitting information data from a sender to a receiver via a transcoder is proposed. The information data comprises confidential information data which is encrypted and non-confidential information data. Security information and transcoding-type information is sent together with the partly encrypted information data to the transcoder which uses the security information and transcoding-type information during a transcoding step. The encrypted confidential information data is thereby transcoded without using its content while the non-confidential information data is transcoded, having access to its content.