Authentication of data in a digital transmission system

1. A method of authentication of data to be sent in a digital transmission system, the data being organized in a hierarchical structure comprising a series of at least three files, comprising the steps of:

generating a first authentication value for at least one first file;

storing said first authentication value in a second file, wherein the second file is a subdirectory hierarchically above the at least one first file;

generating a second authentication value for said second file;

storing said second authentication value in a third file, wherein the third file is a subdirectory hierarchically above the second file; and

transmitting the hierarchical structure comprising said first, second, and third files and the first and second authentication values to a receiver using a transmitter.

2. The method as claimed in claim 1 , further comprising the steps of:

encapsulating the first, second, and third files in a series of tables; and

encapsulating the tables in data packets in a transport packet stream.

3. The method as claimed in claim 2 wherein the transport packet stream conforms to the MPEG standard.

4. The method as claimed in claim 1 , wherein the data files are formatted according to the DSMCC standard.

5. The method as claimed in claim 1 , wherein the second authentication value is generated for the first data file by being applied to at least the first authentication value stored in the second data file.

6. An apparatus for authentication of data to be sent in a digital transmission system, the data being organized in a hierarchical structure comprising a series of at least three files, the apparatus comprising:

a microprocessor for generating a first authentication value for at least one first file;

tangible storage memory for storing said first authentication value in a second file, wherein the second file is a subdirectory hierarchically above the at least one first file;

the microprocessor for generating a second authentication value for said second file;

tangible storage memory for storing said second authentication value in a third file, wherein the third file is a subdirectory hierarchically above the second file; and

a transmitter for transmitting the hierarchical structure comprising said first and second files and the first and second authentication values to a receiver.

7. The apparatus as claimed in claim 6 , further comprising:

the microprocessor for encapsulating the first, second and third files in a series of tables; and

the microprocessor for encapsulating the tables in data packets in a transport packet stream.

8. The apparatus as claimed in claim 7 , wherein the transport packet stream conforms to the MPEG standard.

9. The apparatus as claimed in claim 6 , in which the digital transmission system corresponds to a digital television system.

10. The apparatus as claimed in claim 6 , wherein the data files are formatted according to the DSMCC standard.

11. The apparatus as claimed in claim 6 , wherein the second authentication value is generated for the first data file by being applied to at least the first authentication value stored in the second data file.

12. A method of verification of encapsulated and formatted data received in a digital transmission system, the method comprising the steps of:

reassembling data from encapsulated and formatted data transmitted by the digital transmission system, wherein the received data is organized in a hierarchical structure comprising a first, a second, and a third file, and first and second authentication values, wherein the second file is a subdirectory hierarchically above the first file and comprises the first authentication value for the first file, and wherein the third file is a subdirectory hierarchically above the second file and comprises the second authentication value for the second file; and

verifying, by a microprocessor, the reassembled data by using at least said second authentication value.

13. The method as claimed in claim 12 , wherein the step of verifying is performed by using also said first authentication value.

14. The method as claimed in claim 12 , wherein the data files are formatted according to the DSMCC standard.

15. The method as claimed in claim 12 , wherein the encapsulated and formatted data conforms to the MPEG standard.

16. An apparatus for verification of encapsulated and formatted data received in a digital transmission system, the apparatus comprising:

microprocessor for reassembling data from encapsulated and formatted data transmitted by the digital transmission system, wherein the received data is organized in a hierarchical structure comprising a first, a second, and a third file, and first and second authentication values, wherein the second file is a subdirectory hierarchically above the first file and comprises the first authentication value for the first file, and wherein the third file is a subdirectory hierarchically above the second file and comprises the second authentication value for the second file; and

a microprocessor for verifying the reassembled data by using at least said second authentication value.

17. The apparatus as claimed in claim 16 , wherein the verifying means also uses said first authentication value.

18. The apparatus as claimed in claim 16 , wherein the reassembling means and the verifying means are embodied in a processor.

19. The apparatus as claimed in claim 16 , wherein the digital transmission system corresponds to a digital television system.

20. The apparatus as claimed in claim 16 , wherein the data files are formatted according to the DSMCC standard.

21. The apparatus as claimed in claim 16 , wherein the received encapsulated and formatted data conforms to the MPEG standard.