Device (120), smart card (300) and method for selectively supplying access
to a service (202) encrypted using a control word. A service (202) is
received with an entitlement control message (ECM) (203) comprising
authorization data and a specifier of a validity period of the
authorization data. The service is decrypted only if the ECM (203) is
found valid. The service (202) can be stored on a storage medium such as
a DVD. An ECM transcoding module (211) obtains the authorization data
from the ECM (203) supplies to writing means (215) a device-specific ECM
comprising the authorization data. The device-specific ECM may be
encrypted with a key specific to the device (120) and/or comprise an
identifier for the device (120).