A system for providing scrambled content, comprising a control word
generator, each control word including a control word identifier, a
scrambler for providing a stream of scrambled data packets, and an
encryption device for providing entitlement control messages (ECM's). One
or more consecutive packets are scrambled using the same control word
(CW). Each packet includes a control word identifier identifying the
control word used. The ECM encryption device provides ECM's including a
previous control word (CW.sub.P), a current control word (CW.sub.C) and a
next control word (CW.sub.N). A system for descrambling scrambled content
comprises a descrambler for descrambling the scrambled content and a
decryption device for decrypting ECM's to obtain control words. The ECM
decryption device delivers control words to the descrambler and the
descrambler descrambles the data packets of the scrambled content using a
control word having a control word identifier corresponding with the
control word identifier of the data packet to be descrambled. The system
further comprises a storage device for storing scrambled content and
means to control play back of the stored content, going fast forward and
going backwards. The system is programmed to extract ECM's and to provide
the ECM's to the ECM decryption device for decryption. The system is
programmed to request the ECM decryption device to provide at least a
next control word (CW.sub.N) at play back or going fast forward, and to
provide at least a previous control word (CW.sub.P) and a current control
word (CW.sub.C) at going backwards.