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BR-102025006485-A2 - DECODER FOR DECODING AN AUDIO STREAM FROM AN AUDIO DATA STREAM, APPARATUS FOR RENDERING AN AUDIO DATA STREAM, THEIR RESPECTIVE METHODS, AND AUDIO DATA STREAM.

BR102025006485A2BR 102025006485 A2BR102025006485 A2BR 102025006485A2BR-102025006485-A2

Abstract

This is a method for verifying a media data stream, which has a media stream encoded within it, for reliability, comprising: submitting a predetermined portion of the media data stream, or data derived from it, to a hash function to obtain a hash value; deriving a digital signature from the media data stream; and verifying whether the hash value matches the digital signature to determine whether the media data stream is trustworthy.

Inventors

  • Jonathan PFAFF
  • Tobias Hinz
  • Karsten SÜHRING
  • Heiko Schwarz
  • Karsten GRÜNEBERG
  • Detlev Marpe
  • Thomas Wiegand

Assignees

  • Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.

Dates

Publication Date
20260317
Application Date
20250401
Priority Date
20240402

Claims (20)

  1. 1. Decoder (20) for decoding an audio stream (11) from an audio data stream (14), wherein the decoder is characterized by being configured to decode (63), from the audio data stream, a digital signature (43) to be submitted to a verification (16) of the audio data stream as to reliability by submitting a predetermined portion (13) of the audio data stream, or data derived therefrom, to a hash function (31) to obtain a hash value (33); and verifying (41) the possibility of the hash value fitting the digital signature to determine the possibility of the audio data stream being reliable.
  2. 2. Decoder, according to claim 1, characterized in that the digital signature is transmitted in a supplementary information message of the audio data stream.
  3. 3. Decoder, according to claim 1 or 2, characterized in that the verification of the audio data stream for reliability includes decrypting the digital signature to obtain a verification value; and verifying the likelihood of the hash value matching the verification value.
  4. 4. Decoder, according to any one of claims 1 to 3, characterized by being configured to decode the digital signature from a supplementary information message enriching the audio data stream.
  5. 5. Decoder, according to any one of claims 1 to 4, characterized by verifying the audio data stream for reliability, including locating the predetermined portion within the audio data stream using one or more supplementary information messages interleaved in the audio data stream and determining the predetermined portion as a section of the audio data stream that extends between, or extends from, one or more supplementary information messages.
  6. 6. Decoder, according to claim 5, characterized by being configured to decode the digital signature from one or more supplementary information messages in the audio data stream.
  7. 7. Decoder, according to any one of claims 1 to 4, characterized by verifying the audio data stream for reliability, including locating the predetermined portion within the audio data stream using a prefix supplementary information message and a suffix supplementary information message, interleaved in the audio data stream and determining the predetermined portion as a section of the audio data stream that extends between, or is located between, the prefix and suffix supplementary information messages.
  8. 8. Decoder, according to claim 7, characterized by being configured to decode the digital signature from the supplementary suffix information message.
  9. 9. Decoder, according to any one of claims 6 to 8, characterized by being configured to locate the predetermined portion within the audio data stream using a first supplementary information message and a second supplementary information message, interleaved in the audio data stream and determining the predetermined portion as a section of the audio data stream that extends between, or is located between, the first and second supplementary information messages.
  10. 10. Decoder, according to claim 6 or 7, characterized by being configured to locate the predetermined portion within the audio data stream using a first supplementary information message and a second supplementary information message, interleaved in the audio data stream and determining the predetermined portion as a section of the video data stream that extends between, or is located between, the first supplementary information message and a point in the data stream that is located downstream of the second supplementary information message.
  11. 11. Decoder, according to claim 9 or 10, characterized by being configured to decode the digital signature from the second supplementary information message.
  12. 12. Decoder, according to any one of claims 1 to 11, characterized by being configured to derive from a supplementary overview information message of audio data stream, wherein the supplementary overview information message indicates one or more substreams of the audio data stream with respect to each of which verification of the audio data stream for reliability is possible based on one or more portions in the respective substream.
  13. 13. Decoder, according to any one of claims 1 to 12, characterized by verifying the audio data stream for reliability, including performing the audio data stream reliability verification sequentially with respect to a plurality of portions of the audio data stream, and further verifying whether the hash value and other data derived from submitting a previous portion of the video data stream to the hash function conform to the digital signature, or whether a combined hash value derived by hashing the predetermined portion and an additional hash value obtained by submitting a previous portion of the audio data stream, or additional data derived therefrom, to the hash function, conforms to the digital signature.
  14. 14. Decoder, according to claim 13, characterized by verifying the reliability of the audio data stream, including submitting the predetermined portion and the additional hash value obtained, by submitting a previous portion of the audio data stream or additional data derived therefrom, to the hash function, to a combination to obtain a combined hash value and verifying the possibility of the combined hash value fitting the digital signature.
  15. 15. Decoder, according to claim 14, characterized in that the combination is a concatenation.
  16. 16. Decoder, according to any one of claims 1 to 15, characterized by verifying the reliability of the audio data stream, including further verifying whether a hash function identifier fits the digital signature to determine whether the audio data stream is reliable.
  17. 17. Decoder, according to any one of claims 1 to 16, characterized in that the digital signature is adjusted by a predetermined value in the event of an equality of the predetermined value with a verification value obtained by decrypting the digital signature, or a predetermined portion of the verification value associated with the predetermined value; an equality with the verification value in an additional hash domain, achieved by an additional hash function applied to the predetermined value or to a value concatenation that includes the predetermined value.
  18. 18. Decoder, according to any one of claims 1 to 17, characterized by verifying the audio data stream for reliability, including the use of an asymmetric decryption scheme using a public key.
  19. 19. Decoder, according to claim 18, characterized in that it is configured to derive the asymmetric decryption scheme using first information derived from the data stream.
  20. 20. Decoder, according to claim 19, characterized in that the first information comprises a decryption scheme indicator or a first pointer to a first location from which the asymmetric decryption scheme can be determined, or an identifier of the entity that encoded the audio in the audio data stream.

Description

[001] The embodiments of the invention relate to an apparatus for verifying the reliability of a media data stream, an apparatus for rendering a media data stream with a media stream encoded therein verifiable for reliability, a method for verifying the reliability of a media data stream, a method for rendering a media data stream with a media stream encoded therein verifiable for reliability. Other embodiments relate to a decoder for decoding a media stream, such as a video or audio stream, from a media data stream and an encoder for encoding that media data stream. Other embodiments relate to a media data stream, for example, a video data stream or an audio data stream. [002] Today, the generation, distribution, and consumption of video content and other media content, such as audio, plays an important role in people's lives. International standards, such as the ITU-T recommendations H.264, H.265, and H.266, enable a reliable and interoperable exchange of video content worldwide. Thus, they form a key technology for modern interconnected societies. For audio content, other standards, such as MPEG-AAC (Advanced Audio Coding), are available. [003] Recent rapid developments in artificial intelligence (AI) enable new methods of creating artificial media content, such as the generation of video and/or audio content. In this way, new data formats and innovative ways of user experiences can be achieved. However, at the same time, AI-based methods also run the risk of being used in a deceptive and potentially harmful way. Examples of such misuse are deep fakes that generate a false perception about the provenance or authorship of multimedia content. This can lead to fatal consequences, such as violations of copyright or personal rights, fraud through tampering with evidence, or weakening people's trust in the integrity of public institutions. [004] Thus, there is a need for a concept to verify the reliability of a media data stream, providing a good balance between security level, implementation effort and signaling overhead. [005] This objective is achieved by the object of the independent claims. [006] The embodiments of the invention are based on the idea of rendering a media data stream, for example, whose authenticity must be made verifiable, verifiable for reliability, or by hashing a predetermined portion of the media data stream, and computing a digital signature based on the hash value obtained. For example, the media data stream could be a video data stream, an audio data stream, or a multimedia data stream composed of video and audio. The digital signature is transmitted in the media data stream. The media data stream can then be verified for reliability by subjecting the predetermined portion of the media data stream to the hash function to obtain a hash value and verifying the hash value against the digital signature. Basing reliability verification on the predetermined portion allows for a flexible yet robust reliability verification design, enabling, for example, the inclusion or exclusion of certain parts of the data stream in the predetermined portion and thus in the reliability verification, and/or maintaining certain functionalities, such as random access, for example, by selecting the predetermined portion according to randomly accessible sections, for example, for video, encoded video sequences, CVS, of the data stream. Furthermore, hashing the predetermined portion offers the advantage of reducing the size of the digital signature data, so that the signaling overhead for transmitting the digital signature is kept low. [007] For example, a basic principle on which embodiments of this invention are based is the principle of digitally signing a compressed media bitstream, such as a video bitstream or an audio bitstream. [008] One embodiment of the invention provides an apparatus for verifying the reliability of a media data stream that has a media stream encoded within it. For example, the media data stream is a video data stream with a video encoded within it, or an audio data stream with an audio stream encoded within it. The apparatus is configured to: submit a predetermined portion of the media data stream, or data derived from it, to a hash function to obtain a hash value; derive a digital signature from the media data stream; and verify whether the hash value matches the digital signature to determine if the media data stream is reliable. [009] Another embodiment of the invention provides a decoder for decoding a media stream from a media data stream. For example, the media data stream is a video data stream with video encoded in it, or an audio data stream with audio encoded in it. The decoder is configured to decode, from the media data stream, a digital signature to be subjected to a reliability check of the media data stream by: subjecting a predetermined portion of the media data stream, or data derived from it, to a hash function to obtain a hash value; and verifying whether the has