Broadcasting variants of digital signals in a conditional access system

A method for use in a headend system, the method comprising the steps of:

• generating two or more copies of at least a part of a first digital signal;
• scrambling each copy to obtain scrambled copies of the least a part of the first digital signal, wherein each copy is scrambled differently;
• and
• combining the scrambled copies to obtain a second digital signal within which the scrambled copies are not identifiable as being related to one of the two or more copies of the least a part of the first digital signal so that descrambling, at a receiver of the second digital signal, of the scrambled copies using a decryption key for one of the scrambled copies descrambles said one of the scrambled copies into a meaningful output and all other scrambled copies into a non-meaningful output that an error handler of the receiver discards.

A method for use in a hardware smartcard the method comprising the steps of:

• receiving an entitlement message from a receiver, the entitlement message comprising key data for two or more decryption keys, the entitlement message further comprising the selection data;
• decrypting the entitlement message to obtain the key data and the selection data;
• reading the fingerprint vector from a memory;
• matching the selection data with the fingerprint vector to obtain a matching result;
• and
• obtaining the one decryption key from the key data based on the matching result to enable the receiver to descramble a first scrambled copy of a digital signal into the meaningful output and to descramble a second scrambled copy of the digital signal into the non-meaningful output that an error handler of the receiver discards.

A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions which, when executed by a computer processor cause the computer processor to perform a method comprising:

• generating two or more copies of at least a part of the first digital signal;
• scrambling each copy to obtain scrambled copies of the at least a part of the first digital signal, wherein each copy is scrambled differently;
• and
• combining the scrambled copies to obtain a second digital signal within which the scrambled copies are not identifiable as being related to one of the two or more copies of the at least a part of the first digital signal so that descrambling, at a receiver of the second digital signal, of the scrambled copies using a decryption key for one of the scrambled copies descrambled said one of the scrambled copies into a meaningful output and all other scrambled copies into a non-meaningful output that an error handler of the receiver discards.