A method for controlled delivery of a service from a server (S) to a client (C), includes the steps of sending a download descriptor, from server (S) to client (C), retrieving of the service by the client, sending of a first type confirmation message by the client, activating the service by the client (C), wherein the service is first transformed within the server (S) into a sequence of individual blocks, wherein download descriptor (descn) and first type of confirmation message (confn) are generated and transmitted per at least one block of said sequence, and wherein the first type confirmation message (confn) is sent upon receipt of said at least one block by said client (C). Further improvements include the activation of block n being started before the total contents of block n being received, the first type of confirmation message (confn) for block n being generated upon the complete receipt of block n, and the download descriptor (descn+2) for block n+2 being generated and transmitted upon receipt of said first type confirmation message (confn) for block n.