A method for a receiver device to obtain a control word, the control word for decrypting encrypted content received from a content provider system, the method comprising the receiver device: obtaining a plurality of amounts of key data, wherein, for each amount of key data, said obtaining comprises using one or more corresponding keys to obtain said amount of key data from a secured form of said amount of key data received by said receiver device, and wherein, for each amount of key data, said one or more corresponding keys comprises at least one key shared between the receiver device and a respective security system associated with the content provider system; and obtaining said control word using said plurality of amounts of key data.