EP1472692A1

EP1472692A1 - System and method for the copy-protected and use-protected coding and decoding, transmission, and storage of electronic audio and visual media

Info

Publication number: EP1472692A1
Application number: EP02806311A
Authority: EP
Inventors: Juergen K. Lang; Ursula Maria Bing
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-30
Filing date: 2002-12-03
Publication date: 2004-11-03
Also published as: DE10164135A1; US20050005143A1; AU2002357439A1; WO2003060906A1

Abstract

The invention relates to a system and method for the copy-protected and use-protected coding and decoding, transmission, and storage of electronic audio and visual media. The data contents of the electronic media are prepared, modulated, and coded such that cryptographic decoding processes are required by the recipient who is authorized to make restricted use of said data contents in order to play back or display said data contents in full and that it can be dynamically defined as early as the time of coding to what extent the quality of the display and playback should be reduced and the possible uses should be restricted in case said cryptographic decoding processes are not executed. According to the inventive solution, the electronic audio data and visual data is broken down into uncoded media data and user data, coded media data and user data, key-containing crypto-tune data, and key data allowing the recipient to appropriately use, particularly store, display, and play back in real time, said electronic data in a cost-efficient manner following the transmission and secure decoding thereof.

Description

System and method for copy and usage protected

Encryption and decryption,

Transmission and storage of electronic audio and video media

description

The invention relates to a system and method for copy and usage-protected encryption and decryption, transmission and storage of electronic audio and video media, the data contents of the electronic media being processed, modulated and encrypted in such a way that their complete reproduction or display is carried out in order to carry out cryptographic decryption processes in the case of recipients entitled to a certain scope of use, and that even within the framework of encryption, in the event that such cryptographic decryption processes are not carried out, the extent to which the quality of presentation and reproduction and the possible uses are reduced can be defined dynamically.

It is known that digital electronic media are processed, modulated and encrypted by different methods and systems for different purposes. Such processes generally take place in audio and video technology in order to make the digital data representing the analog audio signals particularly (1) high-quality, (2) robust or (3) compact, or (4) to disrupt unauthorized playback.

1)

The purpose of the high quality is to use the digital data to complete the analogue audio signal as completely as possible to capture. Popular examples of modulation, i.e. the way in which analog audio signals are recorded digitally, are pulse code modulation (PCM), in which the amplitude of the audio signal is sampled at regular intervals in absolute values, or delta modulation, in which the amplitude changes in a certain period of time. When digitizing analog signals, the so-called sampling rate plays a role, i.e. the temporal frequency with which the amplitude of a sound signal is measured (twice the highest measurable and reproducible sound frequency, e.g. 44.1 kHz), as well as the accuracy of the storage of the measured frequency value (rounding eg to 16 bit).

2) The purpose of the robustness of the data is to detect or improve digital errors that occur. This is achieved, among other things. through suitable introduction of additional information (so-called redundancies) and the temporal shifting and interleaving of the digital data stream in relation to the original analog audio signal, in order to distribute larger digital error points into several and possibly even smaller error points in the analog signal that is subsequently restored. A popular method used in the CD system is, for example, error correction according to Reed-Solomon.

3) ^•

The purpose of the compactness of the data is to reduce the amount of data to be transferred or stored to a minimum. In so-called compression processes, a distinction is made between quality-reducing processes (irreversible compression) and those without loss of quality (reversible compression). However, avoiding loss of quality or information is only possible with the reduction and thus loss of important additional information or redundancies, so that permanently strong compression methods are generally irreversible. Target high quality compression processes like For example, the popular mpeg / mp3 method for compressing sound and image data is to reduce the amount of data to a far greater extent than the subjectively (barely) perceptible loss of quality.

4)

With the disruption of unauthorized playback, the aim in the analog TV area in particular is to enable full playback only by using a special decoder. Since in such a decoder there is usually a simple way of decrypting the video signal (analog phase shift), this procedure can basically also be considered under the generic term of encryption. In particular, cryptographic encryption can in principle also be relevant for other applications, for example the electronic transmission of sound and image data. In any case, data values that are relevant for the representation of the analog signal (eg amplitudes or phase values), for example at the transmitter, are encrypted in such a way that only an authorized receiver can decrypt them. Symmetrical or asymmetrical processes or a combination of both (hybrid processes) are often used. In the case of symmetrical methods, the sender and receiver must have the same secret key, which must be exchanged in advance on another transmission path for security reasons. In order to avoid the exchange of the sensitive symmetrical key, asymmetrical methods are alternatively used, in which the transmitter and receiver usually have an asymmetrical key pair consisting of a private and a public key. While the private key always remains with the owner, the public key can be freely distributed and exchanged. The principle of asymmetric encryption is that data that is encrypted with a recipient's public key can only be decrypted with his private key. This means that digital data can be encrypted without sharing secrets.

The problem with all known methods of modulation, error correction, compression and encryption now consists in the fact that these methods have the purpose of representing with as few digital data as possible analog signals which are perceived as subjectively high quality after decoding into the analog domain. Because of their intended use, neither modulation nor error correction or compression are able to protect digital media against the creation of pirated copies or against unauthorized use. The additional encryption of data also only provides partial protection (e.g. in the context of data transmission), since after decryption, the digital sound and image data is available again in unencrypted form and can be copied with any authorization or authorization. All in all, it should be noted with the known methods that they only serve to represent (analog) audio and video signals in the digital domain as audio and video data. Any type of encryption going beyond this is only temporary and is undone before the decoding, ie the conversion back from the digital to the analogue area, takes place.

The bottom line, despite all security procedures and security mechanisms, such as those used to protect modern DVD media, is that digital sound and image data is unencrypted and therefore not protected against the creation of unauthorized copies and unauthorized use as soon as it becomes available or less isolated area of playback and editing equipment. This is a considerable deficiency, especially against the background of open data transfers on the Internet. The invention is based on the object of further developing existing systems and methods for modulating and encrypting electronic audio and video media and their data contents in such a way that they are processed, modulated and encrypted in such a way that their complete reproduction or display is carried out in order to carry out cryptographic decryption processes in the case of recipients who are authorized for a certain scope of use and that, within the scope of encryption, in the event that such cryptographic decryption processes are not carried out, the extent to which the display and reproduction quality and the possible uses are reduced can be defined dynamically.

According to the invention, the object is achieved in that the electronic sound and image data are dynamically divided into unencrypted media and user data, encrypted media and user data, key-containing crypto-melody data and key data, which, after transmission and secure decryption, enable the recipient to use them, in particular enable storage, display and playback in real time, and ensure it is cost-effective.

An advantageous embodiment of the method and a preferred embodiment of the system are distinguished by the fact that the scope of the encryption is variable, so that the ratio between the unencrypted or non-encrypted portion and the encrypted or encrypted portion of the sound and image data is chosen as desired can be.

It is expedient that such a proportionate division of the encrypted and unencrypted portion is also variable over the course of time, so that the extent of the encrypted portion can change during the reproduction of sound and image data.

It is also advantageous that the mention of the proportionate scope of this division of encrypted and unencrypted sound and image data is contained in the unencrypted and / or in the unencrypted user data.

The system and method are expediently characterized in that the crypto-melody data and / or the user data contain information about the use of the encrypted data for the intended use, that is to say the conditions under which the data can be decrypted.

It is advantageous that such conditions, under which the sound and image data may be decrypted, are also variable over time.

It is also expedient that the conditions under which the data can be decrypted contain information about the costs or the tariff class of the respective use with regard to the type of use and the duration of use.

It is also advantageous that the conditions under which the data can be decrypted contain information about whether private or specific or indefinite commercial use is intended.

It is also expedient that the conditions under which the data can be decrypted contain information about how often the audio and visual media can still be reproduced.

It is also advantageous that the conditions under which the data can be decrypted contain information about whether and how often the audio and visual media can still be copied.

Finally, it is advantageous that the conditions under which the data can be decrypted contain information about the genre or another classification of the content of the audio and visual media. An advantageous embodiment of the method and a preferred embodiment of the system are distinguished by the fact that the author, creator, processor or distributor of the electronic audio and video media encrypts or encrypts the unencrypted output data in whole or in part in such a way that it proportionately relates to the unencrypted and split the encrypted media data.

It is expedient that the encryption or encryption of the electronic sound and image media, carried out in whole or in part, is carried out by the author, creator, processor or distributor using a "melody" key which is contained in the crypto melody data in unencrypted or encrypted form is.

It is advantageous that the "melody" key for partial or complete encryption or encryption of the electronic audio and video media, which is contained in the crypto-melody data, is encrypted with a "media" key, which is in encrypted or unencrypted form is included in the key data.

It is also advantageous that the "melody" key for partial or complete encryption or encryption of the electronic audio and video media, which is contained in the crypto-melody data, is valid for a certain period of time, which is shorter than the audio and image data.

It is expedient that the “media” key for decrypting the “melody” keys contained in the crypto melody data is contained in the key data in encrypted or unencrypted form.

It is also expedient that the “media” key contained in the key data is itself encrypted. It is furthermore expedient that the encrypted “media” key contained in the key data for decrypting the “melody” key contained in the cryptomelody data is provided with a trustworthy digital signature.

It is also advantageous that the unencrypted user data contains information about the type and with which “main” and “media” keys the keys for partial or complete decryption or decryption of the electronic audio and video media are encrypted.

An advantageous embodiment of the method and a preferred embodiment of the system are distinguished by the fact that the cryptomelody contains, in chronological order, encrypted information which, after decryption, can be used to decrypt the encrypted media data.

It is advantageous that the crypto melody is encrypted with the “media” key that was used for the encryption of the electronic sound and image media by the author, creator, processor or distributor and that is contained in the key data.

It is also advantageous that the decryption of the media data with the "melody" keys contained in the crypto melody can be carried out with less computation effort than an assumed decryption of the media data encrypted with the "media" key.

It is also expedient that accompanying information on the sound and image data, such as title, artist, etc., is contained in the unencrypted user data.

It is also advantageous that additional accompanying information that is only offered or published for a fee should be light in which encrypted user data are contained.

Further advantages, special features and useful features of the inventions result from the subclaims and the following description of preferred exemplary embodiments.

The present process and system is to be introduced by several companies in the media industry under the project name "m.sec". Special features of m.sec are described below.

With the advent of methods and systems for digital sound and image storage, a new quality of sound piracy arose: Through the so-called "sampling", the previously only analogue sound and image signals were clearly quantified in the course of digitization. With this clear quantification, e.g. In the form of bits and bytes with unique values, perfect copies could be created for the first time, which could no longer be distinguished from the original and therefore showed no qualitative degradations.

After the piracy of recordings had already taken on a considerable volume in the form of illegally created CD copies with the spread of the compact disc, it intensified again with the advent of the Internet. Due to the large volume of data, these were less CD copies or audio files in CD format. Rather, piracy was promoted by a new data format which, due to the high level of data compression, could be used to generate small files that are easily exchangeable over the Internet: the so-called "MP3" format.

MP3 received special support from the "Napster" Internet exchange, which is partly on the verge of legality and partially outside of legality, apparently offered private exchanges between Internet users in general in a public setting and thus promoted the illegal distribution of music tracks to third parties.

After MP3 and Napster at the latest, the media industry has an increased need for a new data format for sound and image data. M.sec meets this need by offering the following advantages:

• Digital sound and image data are no longer published unencrypted, so that they are not perfect

Pirated copies of this original data can be created.

• The decoding of the sound and image data at the recipient is only possible against payment of a usage fee.

• It is possible to levy variable user fees.

• It is possible to reproduce parts of the sound and image data (e.g. the first few seconds of a piece of music or the opening title of a film) without paying a usage fee.

• It is possible to reproduce any part of the sound and image data without paying a usage fee with reduced quality.

• The encrypted sound and image data can be provided with certain usage rights (e.g. number of reproductions and copying processes) and other additional information.

• When the sound and image data are played back, the data are also not transmitted unencrypted. Decryption takes place only with the so-called digital-to-analog conversion (D / A conversion). • With appropriate usage rights, it is possible for the recipient to make copies of the sound and image data after paying a usage fee.

• These personal copies of the sound and image data are "activated" and can be reproduced without further payment of license fees.

• Such copies of the sound and image data that the recipient created after payment of a usage fee cannot easily be used by other recipients.

To meet these requirements, m.sec provides the following architecture:

► The so-called "publisher" distributes electronic sound and image data that is encrypted in whole or in part. (See "publisher" in Fig. 1)

► The recipient has an individual, personalized chip card (the so-called "m.card") which, as a cryptographic module, provides functionalities that cannot be manipulated by him. (Cf. "Cryptographic module for the recipient, m.card" in Fig. 1)

► Corresponding playback and display devices (e.g. personal computer, CD player, Walkman, TV etc.), in combination with the plug-in chip card (m.card), offer the option of correctly reproducing encrypted sound and image data.

The three possible transmission paths, identified as A, B and C, are shown in FIG. 1:

► With transmission path A (e.g. television, TV) there is a continuous, direct reception of sound and image data, in extreme cases in an uninterrupted data stream with no beginning and end. (so-called "streaming") ► With transmission path B, there is usually a remote transmission of audio and video media (e.g. as an Internet download) as dedicated, closed files.

► With transmission path C, the picture and sound information is on physically provided sound and

Image media (e.g. CDs or DVDs) in front of the recipient.

The following application scenarios are provided:

1. Playback of transmitted audio and video media (e.g. broadcast TV program) Should all or part of encrypted content from

If audio and video media are received and played back immediately, the m.card serves as an instrument for encoding between the encryption of the publisher and the playback unit. Here, the encryption by the publisher is reversed within the m.card by decryption, the right to playback is checked and playback is initiated. This conversion is usually associated with costs, e.g. can be tracked in the cryptographic module. In FIG. 1, this corresponds to the transmission path A in connection with the measure for the recipient, identified by the number 1), namely immediate playback.

2. Download and personal activation of sound and image data for subsequent playback

Should fully or partially encrypted content e.g. downloaded from the Internet by download and activated for later personal use, the m.card serves as a conversion tool between the publisher's encryption and personal encryption

Encryption of the m.card. This conversion is usually associated with costs that can be tracked, for example, in the cryptographic module. In FIG. 1, this corresponds to the transmission path B in connection with the measure at the recipient, identified by the number 2), namely the local storage of the Information.

The encryption is canceled by the publisher within the m.card by decryption, the right to create a local copy is checked, the encryption is carried out with the m.card's own key and the creation of a copy is initiated.

3. Reproduction of sound and image data provided by the author on physical media Should all or part of encrypted content from

If audio and video media are reproduced, which are provided on physical media, the m.card serves as a conversion key between the encryption of the publisher and the playback unit.

Here, the encryption by the publisher is reversed within the m.card by decryption, the right to playback is checked and playback is initiated. This conversion is usually associated with costs, e.g. can be tracked in the cryptographic module. In FIG. 1, this corresponds to the transmission path C in connection with the measure for the recipient, identified by the number 1), namely immediate playback. If the audio and video information is not in the decrypted state according to Number 2 temporarily stored in FIG. 1, the information about the first decryption of precisely defined sound and image data can be stored either in the cryptographic module itself or outside the cryptographic module, provided with a digital signature of the cryptographic module, for the repeated reproduction of the unencrypted data be deposited.

4. First and repeated playback of personally activated sound and image data

Should the content of audio and video be unlocked and encrypted again with the m.card's own key Image media are played back, so the m.card serves as a conversion tool. This conversion is usually free of charge, since one-time costs for the activation were raised when the data were originally saved. In Figure 1, this corresponds to the measure marked with the number 3) at the recipient, namely the later reproduction. The m.card's own encryption within the m.card is canceled by decryption and playback is initiated.

5. Disclosure of personally activated sound and image data to (unauthorized) third parties

If the content of audio and video media released and encrypted with the m.card's own key is reproduced to third parties, they will not be able to decrypt it, so that pirated copies cannot be successful. In Figure 1, this corresponds to that with the number

4) marked measure at the recipient, namely the transfer to third parties.

6. Passing on of sound and image data released as re-publishable to third parties (optional)

If the content of audio and visual media (for a separate fee, for example) is activated as "re-publishable" and encrypted again with the m.card's own key, it can be passed on to third parties. However, third parties can decrypt it ( for example, for a fee), as is possible with sound and image data that come directly from publishers.

Coding of sound and image data:

Sound and image data are divided into temporal blocks, so-called

"Frames" divided into a certain length. The sequence of frames results in the contents of the sound and Visual media. The following Figure 2 illustrates the division into frames and areas.

Within each frame (in FIG. 2, two successive frames are shown on the horizontal time axis, labeled "Frame 1" and "Frame 2"), there is a division into six sections (these six sections are shown in FIG. 2 as stacked rectangles are shown, the height of which gives the scope of data on the vertical axis). These six sections are:

1. unencrypted media data ("media.plain") that can be played back without decryption,

2. encrypted media data ("media.cypher"), which are encrypted with the current "melody" key contained in the crypto melody for this frame,

3. unencrypted user data ("data.plain"), which contains information on the title, artist, structure and indexing, genre, accompanying information and last but not least on the time sequence ("dock") (a complete set of unencrypted user data can be over several

Frames),

4. encrypted user data ("data. Cyp her"), which are encrypted with the current "melody" key contained in the crypto melody for this frame and also various information about the title etc. as well as accompanying and checking information and information about usage rights include (a complete set of encrypted user data can span several frames),

5. Key data ("media.key"), which contain an encrypted "media" key, which can be used to decrypt the encrypted "melody" key in the crypto melody and which contains a digital signature or a certificate of this "media" -Key from a trustworthy source (certification authority) which can be used to check the legal ownership and use of this key (a complete set of key data can span several frames) and

6. the so-called "crypto melody" ("melody.key"), the temporary "melody" encrypted with the "media" key - key for decrypting the encrypted media data and information on the authorized use of the audio and video media in relation to the respective one

Contains frame. Typically, a "melody" key always refers to a frame. However, it is possible to use "melody" keys that are valid over several frames.

The key data is optional and can be omitted or replaced with filler data if the corresponding key does not have to be added to the media data.

The proportion between unencrypted and encrypted media data and user data can differ from frame to frame, as can the length of frames. Key data and possibly also user data can be divided into several frames (especially with long keys and additional information). See Fig. 2.

Structure and use of the crypto melody

The crypto melody is an essential security element that significantly increases the overall security of the transmitted data compared to conventional methods without requiring too much additional cryptographic computational effort. The core of the crypto melody is a random number serving as a temporary "melody" key, the validity of which usually extends to one frame. This temporary key is used to decrypt the encrypted rarely media data and the encrypted user data possible.

In order to make the temporary "melody" keys available to the recipient in a protected manner, these are in turn encoded in the crypto melody. The so-called "media" key of the publisher is used to encrypt the temporary "melody" keys. who uses it for a period of one year, for example.

In order to protect the "media" key and to transport it to the recipient, this is - if necessary - in encrypted form in the key data. The so-called "main" key is used to encrypt the "media" key a specially secured cryptographic module is available to the recipient and therefore does not have to be added to the sound and image data.

The purpose of this multi-level encryption, which is illustrated in the so-called “shell model” in FIG. 3 below, is to protect against attacks on the encrypted

Data with the aim of unauthorized decryption of the

Sound and image data. The protection extends in the sense of

"Shells" about the use of several keys in such a way that each key is used to the smallest possible extent.

In Figure 3, the actual electronic data of the sound and image media, which is to be protected, is shown in the inner circle of the "shell model".

This sound and image data is encrypted with the "melody" keys of the next circle or the surrounding shell. These "melody" keys are randomly determined, frequently changing keys that are only valid for a certain amount of time (or "frame"). If one assumes that the "melody key is changed once per second, a total of approximately 40,000 to 100,000 media values (and possibly also user data) are encrypted with this key. This number results if, for example, the sampling rate of 44,100 samples per second, which is common for digital audio signals, is used.

The "melody" keys are in turn encrypted with the "media" key, which is shown in the next circle or the surrounding shell. This "media key will be used by publishers e.g. provided by a certification body once a year. The "media" key is used to encrypt each individual "melody key. Assuming 4000" melody "keys or" frames "changing every second and 100 to 250 published media per year, the total use of a" media "results - Key for approx. 400,000 to 1,000,000 encryption and decryption.

The "media" key is in turn encrypted with the "main key, which is shown in the outermost circle or the outer surrounding shell. This" main "key is used for the lifetime of the cryptographic module m.card. Assuming 4,000 to 10,000 "media" keys are issued to publishers annually, this key would be used approximately 40,000 to 100,000 times over a ten-year period of validity.

By using a temporary "melody" -

A key from the crypto melody for the direct encryption of the sound and image data is uncovered

Key to the success that the image and sound data can be disclosed for the duration of a single frame. It is almost impossible to uncover this key using cryptanalysis, since by definition it is only used to encrypt a limited number of values (only in one frame). A detection of the Key through a so-called "brute force" attack, that is, "trying out" all possible key values, would theoretically be possible if the unencrypted value of the encrypted sound and image data were known and could serve as an indicator of the success of the attack. However, decrypting data that is already decrypted does not justify this effort and is therefore negligible.

By using the publisher's "media" key to encrypt the temporary "melody" -

Key of the crypto melody is difficult to uncover in two ways. Since the number of frames is much smaller than that of the sound and image data itself, a "media" key, which is only used once per frame, is used much less often than a "media" -

Key that would be used to encrypt sound and image data. Because of the comparatively rare

Use of the "media" key therefore reduces the risk of the key being uncovered by cryptanalysis, since a key can be uncovered more and more easily with increasing use via the cryptanalysis method. Because the values to be decrypted are temporary "Melody key around

A random value, a "brute force" attack is also practically impossible due to the missing target value.

The use of the "master key for encrypting the" media "key also makes it difficult to uncover it in two ways. Since the" master key is used only very rarely, for example once per publisher and year, the risk of Decryption of the key by cryptanalysis reduced, since a key can be discovered more easily with increasing use via cryptanalysis. Even for a "brute force" attack, the few target values do not offer sufficient clues.

Claims

claims

1. System and method for copy and usage-protected encryption and decryption, transmission and storage of electronic audio and video media, the data contents of the electronic media being prepared, modulated and encrypted in such a way that their complete reproduction or display is the implementation of cryptographic decryption processes In the case of recipients authorized in a certain scope of use, and that even within the framework of encryption in the event that such cryptographic decryption processes are not carried out, the extent to which the presentation and reproduction quality and the possible uses are reduced is characterized by the fact that the electronic sound and Image data is dynamically divided into unencrypted media and user data, encrypted media and user data, key-containing crypto-melody data and key data, which are based on a Transmission and secure decryption at the recipient's use, in particular the storage, display and playback in real time, enable and ensure cost-effective.

2. The method as claimed in claim 1, that the scope of the encryption is variable, so that the ratio between the unencrypted or non-encrypted portion and the encrypted or encrypted portion of the sound and image data can be chosen as desired.

3. The method according to one or both claims 1 or 2, characterized in that a such proportionate division of the encrypted and unencrypted part is also variable over time, so that the extent of the encrypted part can change during the reproduction of sound and image data.

4. The method according to one or more of claims 3 to 3, ie that the proportionate scope of this division of encrypted and unencrypted sound and image data is included in the unencrypted and / or in the unencrypted user data.

5. The method according to one or more of claims to 4, d a d u r c h g e - k e n n z e i c h n t that

Cryptomelody data and / or the user data contain information about the use of the encrypted data for the intended use, that is to say the conditions under which the data can be decrypted.

6. The method as claimed in claim 5, that the conditions under which the sound and image data can be decrypted are also variable over the course of time.

7. The method according to one or both claims 5 or 6, d a d u r c h g e k e n n z e i c h n e t that the conditions under which a decryption of the

Data may take place, contain information about the costs or the tariff class of the respective use with regard to the type of use and the duration of use.

8. The method according to one or more of claims 5 to 7, d a d u r c h g e k e n n z e i c h n e t that the conditions under which a decryption of the data may take place contain information about whether a private or a specific or indefinite commercial use is intended.

9. The method according to one or more of claims 5 to 8, d a d u r c h g e - k e n n z e i c h n e t that the

Conditions under which the data can be decrypted contain information about how often the audio and visual media can still be played.

10. The method as claimed in one or more of claims 5 to 9, that the conditions under which the data may be decrypted contain information about whether and how often the audio and video media may still be copied.

11. The method according to one or more of claims 5 to 10, d a d u r c h g e k e n n z e i c h n e t that the conditions under which a decryption of the

Data may take place, contain information about the genre or another content classification of the audio and visual media.

12. The method according to one or more of claims 1 to 5, characterized in that the author, creator, editor or distributor of the electronic audio and video media fully or partially encrypted or encrypted the unencrypted output data in such a way that they proportionately to the the unencrypted and the encrypted media data are divided.

13. The method according to claim 12, since - marked - characterized in that the encryption or encryption of the electronic sound and image media carried out in whole or in part by the author, creator, processor or distributor is carried out using a "melody" key which is in unencrypted form. page or encrypted form is contained in the crypto melody data.

14. The method according to one or more of claims 12 or 13, d a d u r c h g e k e n n z e i c h n e t that the "melody" key for partial or complete

Encryption or encryption of the electronic audio and video media contained in the crypto melody data is encrypted with a “media” key that is contained in the key data in encrypted or unencrypted form.

15. The method according to one or more of claims 12 to 14, d a d u r c h g e k e n n z e i c h n e t that the "melody" key for partial or complete

Encryption or encryption of the electronic sound and image media contained in the crypto-melody data is valid for a certain period of time that is shorter than the sound and image data to be reproduced.

16. The method according to one or more of claims 12 to 15, characterized in that the "media" key for decrypting the "melody" key contained in the crypto-melody data is contained in the key data in encrypted or unencrypted form.

17. The method according to one or more of claims 12 to 16, so that the "media" key contained in the key data is itself encrypted.

18. The method according to one or more of claims 12 to 17, so that the encrypted "media key" contained in the key data for decrypting the "melody" key contained in the crypto-melody data is provided with a trustworthy digital signature.

19. The method as claimed in one or more of claims 12 to 18, ie that the unencrypted user data contain information about the type and with which

"Main" and "Media" keys are the keys for partial or complete decryption or decryption of the electronic audio and video media.

20. The method according to one or more of claims 12 to 19, so that the crypto melody contains encrypted information in chronological order, which after its decryption can be used to decrypt the encrypted media data.

21. The method according to claim 20, characterized in that the crypto melody is encrypted with that “media” key, which was used for the encryption of the electronic sound and image media by the author, creator, processor or distributor and which is contained in the key data.

22. The method according to one or more of claims 20 or 21, characterized in that the decryption of the media data with the "melody" keys contained in the crypto melody can be carried out with less computation effort than an assumed decryption of the ones encrypted with the "media" key media data.

23. The method according to one or more of claims 20 to 22, d a d u r c h g e k e n n z e i c h n e t that accompanying information on the sound and image data such as title, artist etc. are contained in the unencrypted user data.

24. The method according to one or more of claims 20 to 23, so that additional accompanying information, which is only to be offered or published for a fee, is contained in the encrypted user data.