CHECKING THE DEGREE OF TRUST OF MULTIMEDIA DATA STREAMS

Claims

1. A decoder (20) for decoding an audio stream (11) from an audio data stream (14), wherein the decoder is configured to: decode (63) from the audio data stream a digital signature (43) against which the audio data stream is to be verified (16) for the degree of trust by: applying a hash function (31) to a predetermined portion (13) of the audio data stream or data extracted therefrom to obtain a hash value (33); and checking (41) whether the hash value matches the digital signature to determine whether the audio data stream is trusted.

2. The decoder according to paragraph 1, wherein the digital signature is transmitted in a message with additional information in the audio data stream.

3. A decoder according to claim 1 or 2, wherein checking the audio data stream for a degree of trust comprises: decrypting the digital signature to obtain the verification value; and checking whether the hash value matches the check value.

4. A decoder according to any one of paragraphs 1-3, configured to decode a digital signature from a message with additional information in an audio data stream.

5. A decoder according to any one of claims 1 to 4, wherein checking the audio data stream for a degree of trust includes determining the location of a predetermined portion in the video data stream by using one or more additional information messages embedded in the video data stream, and determining the predetermined portion as a section of the video data stream extending between or extending from the one or more additional information messages.

6. The decoder of claim 5, configured to decode a digital signature from one of one or more additional information messages in the audio data stream.

7. A decoder according to any one of claims 1 to 4, wherein checking the audio data stream for a degree of trust includes determining the location of a predetermined portion in the audio data stream by using a prefix message with additional information and a suffix message with additional information embedded in the audio data stream, and determining the predetermined portion as representing a section of the audio data stream extending between or located between the prefix and suffix messages with additional information.

8. A decoder according to claim 7, configured to decode a digital signature from a suffix message with additional information.

9. A decoder according to any one of claims 6 to 8, configured to determine the location of a predetermined portion in an audio data stream by using a first additional information message and a second additional information message embedded in the audio data stream and determining the predetermined portion as representing a section of the audio data stream extending between or located between the first and second additional information messages.

10. A decoder according to claim 6 or 7, configured to determine the location of a predetermined portion in an audio data stream by using a first additional information message and a second additional information message embedded in the audio data stream and determining the predetermined portion as representing a section of the video data stream extending between or located between the first additional information message and a point in the data stream that is located downstream of the second additional information message.

11. A decoder according to claim 9 or 10, configured to decode a digital signature from a second message with additional information.

12. A decoder according to any one of claims 1-11, configured to extract a review message with additional information from an audio data stream, wherein the review message with additional information indicates one or more substreams of the audio data stream, in relation to each of which checking of the audio data stream for a degree of trust is possible based on one or more parts in the corresponding substream.

13. A decoder according to any one of paragraphs 1-12, in which checking the audio data stream for a degree of trust comprises performing checking the audio data stream for a degree of trust sequentially with respect to a plurality of parts of the audio data stream and further by checking whether: whether the hash value and additional data obtained from applying the hash function to the previous part of the video data stream correspond to the digital signature, or whether the combined hash value obtained by hashing the predetermined portion and the additional hash value obtained by applying the hash function to the previous portion of the audio data stream or additional data extracted therefrom corresponds to the digital signature.

14. The decoder of claim 13, wherein checking the audio data stream for a degree of trust includes subjecting the predetermined portion and an additional hash value obtained by applying a hash function to the previous portion of the audio data stream or additional data extracted therefrom to combining to obtain a combined hash value, and checking whether the combined hash value corresponds to the digital signature.

15. The decoder of claim 14, wherein said combination is a concatenation.

16. The decoder of paragraphs 1-15, in which checking the audio data stream for a degree of trust includes additionally checking whether the identifier matches the hash function of the digital signature to determine whether the audio data stream is trusted.

17. A decoder according to any one of paragraphs 1-16, in which the compliance of the digital signature with a predetermined value is ensured in the event of: equality of the predetermined value with a check value obtained by decrypting the digital signature or a predetermined portion of the check value associated with the predetermined value, or equality with a check value in an additional hashed region, achieved by means of an additional hash function applied to a predefined value or to a concatenation of a value that includes the predefined value.

18. A decoder according to any one of claims 1 to 17, wherein checking the audio data stream for a degree of trust includes using an asymmetric decryption scheme using a public key.

19. The decoder of claim 18, configured to obtain an asymmetric decryption scheme using the first information extracted from the data stream.

20. The decoder of claim 19, wherein the first information comprises an indicator of a decryption scheme or a first pointer to a first location from which an asymmetric decryption scheme can be determined, or an identifier of the entity that encoded the audio into the audio data stream.

21. A decoder according to any one of paragraphs 18-20, configured to obtain a public key using second information extracted from the data stream.

22. The decoder of claim 21, wherein the second information comprises a second pointer to a second location from which a public key or an identifier of the entity that encoded the audio into the audio data stream can be retrieved.

23. A decoder according to any one of paragraphs 1-22, configured to obtain a hash function using third information extracted from the data stream.

24. The decoder of claim 23, wherein the third information comprises a hash function indicator or a third pointer to a third location from which the hash function can be determined, or an identifier of the entity that encoded the audio into the audio data stream.

25. A decoder according to any one of paragraphs 1-24, wherein the hash value depends on each bit of a predetermined portion of the audio data stream.

26. A decoder according to any one of claims 1 to 25, wherein checking the audio data stream for a degree of trust comprises checking that the hash function is correct by checking whether the parameterization or identifier of the hash function matches the digital signature.

27. A decoder according to any one of claims 1 to 26, configured to provide a predetermined portion for subjecting it, along with additional data extracted from a portion of the multimedia stream accompanying the audio data stream, to a check of the degree of trust of the audio data stream combined with the multimedia stream.

28. A device (15) for generating a stream (14) of audio data into which an audio stream is encoded that is checked for a degree of trust, wherein the device is configured to: apply a hash function (31) to a predetermined portion (13) of the audio data stream or data extracted therefrom to obtain a hash value (33); compute a digital signature (43) based on a hash value for a digital signature hash function; and insert (77) a digital signature into the audio data stream, thereby providing the ability to determine whether the audio data stream is trusted by checking whether the hash value of the digital signature matches.

29. The device of claim 28, configured to insert a digital signature into a message with additional enhancement information in the audio data stream.

30. The device according to claim 28 or 29, configured to calculate a digital signature based on a hash value by means of: generating a verification value based on the hash value, encrypting the verification value to obtain a digital signature.

31. The device according to any one of paragraphs 28-30, wherein the device is an encoder configured to: encoding an audio stream into an audio data stream, and encoding a digital signature into the audio data stream.

32. The device according to claim 31, configured to encode a digital signature into a message with additional information in an audio data stream.

33. The apparatus of claim 31 or 32, wherein the location of the predetermined portion is determined in the audio data stream by using one or more additional information messages embedded in the audio data stream and defining the predetermined portion as a section of the audio data stream extending between or extending from the one or more additional information messages.

34. The device of claim 33, configured to encode a digital signature into one of one or more messages with additional information in the audio data stream.

35. The apparatus of claim 31 or 32, wherein the location of the predetermined portion is determined within the audio data stream by using a prefix additional information message and a suffix additional information message embedded within the audio data stream, and defining the predetermined portion as representing a section of the audio data stream extending between or located between the prefix and suffix additional information messages.

36. The device according to claim 35, configured to encode a digital signature into a suffix message with additional information.

37. The apparatus of claim 31 or 32, wherein the location of the predetermined portion is determined in the audio data stream by using a first additional information message and a second additional information message embedded in the audio data stream and defining the predetermined portion as representing a section of the audio data stream extending between or located between the first and second additional information messages.

38. The apparatus of claim 31 or 32, wherein the location of the predetermined portion is determined in the audio data stream by using a first additional information message and a second additional information message embedded in the audio data stream and defining the predetermined portion as representing a section of the audio data stream extending between or located between the first additional information message and a point in the data stream that is located downstream of the second additional information message.

39. The device of claim 35, configured to encode a digital signature into a second message with additional information.

40. The device according to claim 31 or 32, configured to insert a review message with additional information into an audio data stream, wherein the review message with additional information indicates one or more substreams of the audio data stream, in relation to each of which checking of the audio data stream for a degree of trust is possible based on one or more parts in the corresponding substream.

41. The device according to any one of paragraphs 28-39, in which the checking of the audio data stream for the degree of trust can be performed sequentially with respect to a plurality of parts of the audio data stream and additionally by: calculating a digital signature based on the hash value and additional data obtained by applying the hash function to the previous portion of the video data stream, or calculating a digital signature based on a combined hash value obtained by hashing a predetermined portion and an additional hash value obtained by applying a hash function to the previous portion of the audio data stream or additional data extracted therefrom.

42. The device of claim 41, configured to combine the predetermined value and the additional hash value obtained by applying the hash function to the previous portion of the audio data stream or additional data extracted therefrom to obtain a combined hash value, and to calculate a digital signature for digitally signing the combined hash value.

43. The device of claim 42, wherein said combination is a concatenation.

44. A device according to any one of paragraphs 41-43, configured to additionally calculate a digital signature based on the hash function identifier.

45. A device according to any one of paragraphs 28-44, configured to calculate a digital signature based on a hash value by: generating a verification value based on the hash value such that the hash value matches a predetermined portion of the verification value, and encrypting the verification value to obtain a digital signature, or generating a verification value based on the hash value by further hashing a predetermined value or concatenating values ​​including the predetermined value and encrypting the verification value to obtain a digital signature.

46. ​​A device according to any one of paragraphs 28-45, configured to calculate a digital signature based on a hash value by using an asymmetric encryption scheme using a public key and a private key.

47. The device of claim 46, configured to insert extractable first information into a data stream, from which an asymmetric encryption scheme can be obtained.

48. The device of claim 47, wherein the first information comprises an indicator of an encryption scheme or a first pointer to a first location from which an asymmetric encryption scheme can be determined, or a device identifier.

49. A device according to any one of paragraphs 28-48, configured to insert into the audio data stream extractable second information, based on which an extraction of the public key can be obtained.

50. The device of claim 49, wherein the second information comprises a second pointer to a second location from which the public key can be retrieved, or a device identifier.

51. A device according to any one of paragraphs 28-50, configured to insert into the data stream third information from which a hash function can be obtained.

52. The device of claim 51, wherein the third information comprises a hash function indicator or a third pointer to a third location from which the hash function can be determined, or a device identifier.

53. The apparatus of any one of paragraphs 28-52, wherein the hash value depends on each bit of a predetermined portion of the audio data stream.

54. A device according to any one of paragraphs 28-53, configured to calculate a digital signature additionally based on, and due to this, a digital signature, parameterization or identifier of the hash function.

55. A method (200) for decoding an audio stream from an audio data stream, wherein the method comprises the step of: decoding (163) from the audio data stream a digital signature, according to which the audio data stream is to be verified for the degree of trust, wherein the verification comprises: applying (131) a hash function (31) to a predetermined portion of the video data stream or data extracted therefrom to obtain a hash value (33); checking (141) whether the hash value matches the digital signature to determine whether the audio data stream is trusted.

56. A method (150) for generating an audio data stream into which an audio stream is encoded that is checked for a degree of trust, wherein the method comprises the steps of: apply (131) a hash function to a predetermined portion of the audio data stream or data extracted therefrom to obtain a hash value; calculate (171) a digital signature based on the hash value for digitally signing the hash function; and insert (177) a digital signature into the audio data stream, thereby providing the ability to determine whether the audio data stream is trusted by checking whether the hash value of the digital signature matches.

57. An audio data stream generated by the method according to claim 56.