Time stamping and time stamp validity verification system, method and device in a digital broadcasting environment

• US 20040049681A1
• Filed: 06/27/2003
• Published: 03/11/2004
• Est. Priority Date: 07/13/2000
• Status: Abandoned Application

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Diehl, Eric, Letellier, Philippe
• Application Number:
  US10/332,675
• Publication Number:
  US 20040049681A1
• Time in Patent Office: Days
• US Class Current: 713/178
• CPC Class Codes: A63F 2300/409 Data transfer via television network
• CPC Class Codes: H04H 60/33 Arrangements for monitoring the users' behaviour or opinions
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• CPC Class Codes: H04N 21/4758 for providing answers, e.g. voting
• CPC Class Codes: H04N 21/63775 for uploading keys, e.g. for a client to communicate its public key to the server key management H04L9/08; network support of key management H04L63/06
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests

Abstract

The invention relates in particular to a process for timestamping digital data comprising:

an operation (902) of defining a sequence (CS) of services comprising at least one service (TSS), each service being chosen within a list of services (TSS) according to a method of choice giving a variable result for each occurrence of the operations (902) of defining a sequence of services; and

an operation (807) of collecting a sequence of timestamp information elements, according to which at least one information element (TSI(CS[i])) is extracted from each service (CS[i]) of the sequence of services (CS) to form the elements of the sequence of information elements, each information element comprising an information item representative of a current timestamp.

Claims

1. A process for timestamping digital data, characterized in that it comprises

an operation (902) of defining a sequence (CS) of services comprising at least one service, each said service being chosen within a list of services (TSS) according to a method of choice giving a variable result for each occurrence of said operations (902) of defining a sequence of services;

and

an operation (807) of collecting a sequence of timestamp information elements, according to which at least one information element (TSI(CS[i])) is extracted from each service (CS[i]) of said sequence of services (CS) to form the elements of said sequence of information elements, each information element comprising an information item representative of a current timestamp.

2. The timestamping process according to claim 1, characterized in that said list of services (TSS) comprises at least one service.

3. The timestamping process according to one of claims 1 or 2, characterized in that said method of choice giving a variable result is a method of random or pseudo-random drawing.

4. The timestamping process according to any one of claims 1 to 3, characterized in that it comprises a step (802) of transmission and/or of reception of a message (TSC) comprising the number of services (SCH) of said sequence of services (CS) and said list of services.

5. The timestamping process according to any one of claims 1 to 4, characterized in that it comprises an operation (908) of constructing a timestamped group of data comprising:

a group of information items comprising;

said digital data (A);

an identifier (service_number) of each of the services of said sequence of services;

said sequence of timestamp information;

and a signature (total_signature) of at least one element of said group of information items.

6. The timestamping process according to claim 5, characterized in that it furthermore comprises an operation (807) of collecting a sequence of information signatures (SIGN), each of the signatures being associated in a one-to-one manner with each of said timestamp information items and signing an information item comprising said timestamp information item (current_time) and an identifier of said service (Service[i]) from which it arises,

and in that said timestamped group of data furthermore comprises said sequence of information signatures (SIGN).

7. The timestamping process according to any one of claims 1 to 6, characterized in that:

each timestamp information item furthermore comprises the definition (CDef) of a retrieval challenge to be extracted from said list of services; and

the timestamping process furthermore comprises an operation (807) of extracting an answer (Ret_C) corresponding to said definition (CDef) of each said retrieval challenge.

8. The timestamping process according to claim 7 dependent on one of claims 5 or 6, characterized in that said timestamped group of data furthermore comprises said answer (Ret_C).

9. The timestamping process according to claim 8, characterized in that each timestamp information item furthermore comprises an imprint (hashed_correct_answer) of said answer.

10. The timestamping process according to any one of claims 5, 6, 8 or 9, characterized in that it comprises an operation (909) of transmitting said timestamped group of data.

11. A process for verifying the timestamp validity of digital data, characterized in that it said timestamp has been generated by a process for timestamping said digital data according to any one of claims 1 to 10.

12. The process for verifying the timestamp validity of digital data according to claim 11, characterized in that it performs a verification of at least one group of data which may be timestamped by a timestamping process according to any one of claims 5, 6, 8 or 9.

13. The process for verifying timestamp validity according to claim 12, characterized in that said verifying process comprises at least one operation of verification forming part of the group comprising:

an operation (1002) of verifying signature (total signature) of a group of data;

an operation (1003) of verifying a number of services (SCH) requested;

a verification operation (1006) attesting that each timestamp information item indeed corresponds to a requested service;

an operation (1006) of verifying the validity of an answer to a possible requested retrieval challenge for each timestamp information item; and

an operation (1008) of verifying the consistency of timestamping extracted from a group of timestamped data.

14. The process for verifying timestamp validity according to one of claims 12 or 13, characterized in that it comprises an operation (1009) of sending said validated digital data.

15. A system characterized in that it comprises means for implementing:

a process for broadcasting services, each of said services containing information elements representative of a timestamp;

a timestamping process according to one of claims 1 to 10; and

a process for verifying timestamp validity according to any one of claims 11 to 14.

16. A device for timestamping digital data, characterized in that it comprises means (200, 207, 400, or 500) suitable for implementing a timestamping process and/or a process for verifying timestamp validity according to any one of claims 1 to 14.

17. A device for timestamping digital data, characterized in that it comprises:

a means of defining a sequence (CS) of services, each of the services being chosen within a list (TSS) of services comprising at least one service according to a method of choice giving a variable result for each use of said means of defining a sequence of services; and

a means of collecting a sequence of timestamp information elements, extracting an information element (TSI(CS[i])) from each service (CS[i]) of said sequence (CS) of services to form the elements of said sequence of information elements, each information element comprising an information item representative of a current timestamp.

18. A device for verifying the timestamp validity of digital data, characterized in that it comprises at least one means of verification forming part of the group comprising:

a means of verifying signature of a group of data;

a means of verifying a number of services requested;

a verification means attesting that each timestamp information item indeed corresponds to a requested service;

a means of verifying the validity of an answer to a possible requested retrieval challenge for each timestamp information item; and

a means of verifying the consistency of timestamping extracted from a group of timestamped data.