a transmitter real time clock 706 a transmitted encrypted time code 708 and a transmitted encrypted digital content stream 710 the transmitter real time clock 706 is used by the transmitter to obtain a time code that is used to define a window of opportunity during which the encrypted data key 702 is valid for decrypting the encrypted digital content stream 710 the time code is encrypted by the transmitter not shown and must be decrypted by a receiver using an appropriate key 0072 fig8 illustrates an embodiment in which the trusted entity is contained within alternatively is under the control of the transmitter fig8 includes a transmitting entity 800 a trusted entity 802 a data key 804 a transmitter broadcast 806 a transmitter real time clock 808 a transmitted encrypted data key and time code 810 and a transmitted encrypted digital content stream 812 in this embodiment the transmitter receives a data key 804 from the trusted entity 802 and uses the data key to encrypt and transmit the digital content stream 812 the transmitter 806 also combines the data key with a time code defining a window or opportunity encrypts these and transmits the combination 810 it will be appreciated that the transmissions are being made via a communications network not shown and that in a specific embodiment the communications network is the internet 0074 fig9 is a partial block diagram that illustrates another specific embodiment of a transmitter designated generally by the reference numeral 900 the transmitter 900 includes a data key 902 a received digital content stream 904 a circuit 906 for encrypting the received digital content stream and transmits an encrypted digital content stream 908 the transmitter 900.