DE19950267C2 - Device and method for the copy-protected distribution of electronic documents - Google Patents

Description

The present invention relates to a device for knockout distribution of electronic documents in one publicly accessible, electronic data network, esp especially the Internet, according to the generic term of the patent Proverb 1. The present invention further relates to Process for the copy-protected distribution of electronic Documents, in particular for operating such a pre direction.

Due to the rapidly expanding use of the Internet as a medium for distribution, exchange and distribution electronic documents - this will be discussed in the present Case in addition to text files in particular audio, video, Animation, simulation and program files as well as mixing forms counted from these - increasingly turns the pro effective access control in particular valuable, copyrighted files and a ver prevention of unauthorized disclosure without authorization copies.

Current common procedures, the copyright protection of electronically distributed over public data networks Improving tronic (user) files affects one on the one hand, classic forms of encryption of such users files, on the other hand it is now also common in (legally placed on the market) copies of an elec tronic document so-called electronic watermark to introduce, namely individualizing electronic Markings that - for a user of the document in the normal use invisible - nevertheless the exact iden enable an existing document (with the possible goal of spreading the origin for unjustified to be able to identify copies).  

However, both approaches have the disadvantage that especially once towards private end users (unencrypted or decrypted) in traffic brought document copy from end user for private purposes chiven and used, with the result that the Urhe About that is reflected in an electronic file Works considerable damage from such users that is owned by an unauthorized (and usually copy also purchased free of charge, and a landlord economic advantage (reward) over those that arise who would otherwise have acquired the document properly.

The distribution of Music files over public data networks, especially that Internet, and it is assumed that not only that Internet to an important (if not dominant) me dium for the electronic distribution of musical works will also grow with the attractiveness of this sales channel the potential risk and damage from piracy rer, who in turn use the Internet to Raubko pien open to the public free of charge to ma chen.

Specifically, for example in the case of electronically via the Audio files to be distributed on the Internet, the MP3 file format developed as a standard, both legally acquired, as also as pirated copies of so-called pirate sites (i.e. unauthori operated, pirated servers on the Internet net) downloaded MP3 files using additional programs common Internet service programs, so-called viewers (i.e. from play equipment for such an electronic file), from one Viewers can be used.

The explosively expanding number of pirate Sites that are often based on geographic server locations be operated where a procedure with means of the author on the right is impractical, exacerbates the need for effective options for the controlled distribution of electronic  Documents, especially copyright rele vanter works, such as pieces of music, video clips, films etc., thus not an uncontrollability of the electronic Dissemination of such documents the underlying, make artistic and creative activities unattractive and brings it to a standstill.

The problem of a copy-protected distri is exacerbated bution of electronic documents on the Internet by that effective control of the playback units on Be user side is practically impossible. Again using the example of music files (MP3 format) shows that practical the creation of electronic files (documents) in the Unavoidable MP3 format from digital sound carriers (CD) is, just like the other way around, creating music CDs from MP3 files. An effective functional limitation of an MP3 Players alone is not possible because always when opening (playing) an electroni the direct access to the digital data tenstrom and thus already a copy (digital and so that without loss of quality) can be created, the so-called Local loopback problem.

The object of the present invention is therefore to provide a direction for copy-protected distribution of electronic do documents in a public electronic data network, especially on the Internet, according to the generic term of the An Proverb 1 to create, in favor of a document can be achieved that on the one hand a Thursday document users only authorized electronic documents (usually after a financial Transaction to satisfy the interest of the document provider ters) can perform, and what also beyond Opportunities are created for further dissemination electronic documents already on pirate sites make it unattractive and contain it.

From US 5,889,860 to the prior art is a front direction for copy-protected distribution of electronic do documents in a publicly accessible electronic file network, namely the Internet.

More specifically, this device for copying disclosed protect distribution of sheet music documents in electronic Form an access unit assigned to a user, the is connected to the electronic data network and for Perform a loading access and to open a loaded one an electronic (note) document by means of a re delivery unit is formed. A document is also disclosed ten server unit, which enable charging access to an egg to be selected via the electronic data network A plurality of offers from the document server unit NEN documents are trained. The electronic document has the document data in a document data structure.

In addition, it is known from this prior art that the electronic document by means of an electroni encryption unit to generate an encrypted rarely form of the electronic document as well as a drawn key key file can be encrypted; the ver key form of electronic document stands out characterized by the fact that this encrypted form for the User is useless.

It is also known that the user via the electro niche data network a key file for a later Ent keys can be obtained, the user-side Zu handle unit is assigned to a local unit, which, using the key to restore the electronic document in the usable, usable and unencrypted form.  

The task is accomplished by the device with the features of claim 1 and the method with the features of claim 13 solved; advantageous further training are described in the subclaims.

The distribution takes place electronically in the manner according to the invention documents, such as MP3 audio files or JPEG Image files with the help of Internet document servers, in encrypted form instead, according to the invention the ver keyed form of the respective electronic documents like this looks like the fact of encryption by the participating computer or computer units without content che examination of the document in question is not recognizable. In other words, an encrypted MP3 audio file sees with regard to their data format or their file structure just like an unencrypted MP3 Audio file, and only by playing (opening) the Da part with an appropriate player (viewer) shows that the encrypted file is a useless, common one completely confusing and make no sense of content of the result.

In addition to the Si already achieved by encryption security (an unauthorized user of the encrypted The file will not use it and will only continue encrypted can give), the procedure according to the invention offers the Possibility of using a large number of fiction according to encrypted electronic documents existing document server units, in particular Pira ten sites, and so on, depending on volume and type number of uploaded, encrypted documents, for ensure that access to the relevant server unit User after multiple finding that a lengthy and laboriously downloaded MP3 audio file (the one with a short, about 3-minute piece of music already orders of magnitude of several MBytes) may lose interest and may be inclined to the electronic Obtain document legally and easily and not  the encrypted and unusable file fold to delete.

The present invention also covers this possibility from: The Si natural unit applied or naturally contained therein electronic marking (signature) identifies the elek tronic document regarding the for the document on Decrypt the necessary reconstruction file clearly, so that the electronics stuck to the encrypted document proper data marking (signature) can be used can, in order by means of the assignment unit (approximately in the manner ei relational database system) either immediately the necessary reconstruction file or instructions access the database, or one (Internet ) To receive the address (e.g. as a hyperlink), via which then a corresponding reconstruction server with the necessary file can be accessed.

This link can then be found in the for the originator of the elektroni desired document as the basis for a Transaction and settlement process are made in namely an accessing user who is responsible for the elec tronic signature of the downloaded ver keyed document searches for suitable reconstruction file, these against appropriate remuneration and / or registration is provided, this reconstruction da tei in particular also perform other control functions can, for example, a right of a Be user to access the unencrypted document, the right to access only parts of the document (e.g. to to play a song), etc.

The present invention offers numerous implementations possibilities, and should only be exemplary, also in the following description of an embodiment, on Au Dio file formats, such as MP3, are referred to. in the The term encompasses the scope of the invention  "Document data structure" therefore also any, in an elec tronic file occurring, structure or format inherent te, limited information components (also "data package" called; further examples are so-called frames in video or Audio files, or individual words or sentences in text documentation ment), which is a content-related or content-related manipulation Enable encryption for the purpose of encryption without the data format (data structure) character of the green changes the file format.

A particularly inexpensive way of using this encryption to effect within the scope of the present invention is So-called semantic encryption, as used by the applicant in German patent application 199 32 703.3 is disclosed, and those regarding the modalities of contextual and in content-dependent encryption as full in the this application should apply included.

In concrete terms, this enables the training provided swapping, removing, adding and / or exchanging the achievement of the individual content-effective components an encrypted document, which, in the invented according to the manner desired in terms of its structure indistinguishable from an unencrypted document is, however in terms of content - about as Video sequence with completely disjointed (partially wrong loin) single images or interchanged intermediate images, (so-called intraframes) - no utility for an unauthori based user has more.

It is within the scope of the present invention the signature verification and management as well as the assignment the respective reconstruction files in one hand (i.e. e.g. with the document provider), is alternative in particular also provided in the manner of an Internet wide network of different document providers, one To provide a plurality of reconstruction server units, to the then preferably central, common allocation units  through appropriate hyperlinks or other links pointing out methods of

Even if not behind everyone, within the scope of the present Invention copy-protected distribution automatically a un indirect financial interest of a document provider must stand (often it should be of actual interest correspond rather to keep control and just thinning unauthorized distribution), just comes with increasing commercialization of the Internet and the Establishing the Internet as an effective sales channel for Audio files suitable billing modalities a particular their importance.

According to a further development, it is therefore provided that the user zer, which is already from a document server unit has obtained a (encrypted) copy of the document, the order the encryption was established when trying to play provides, and then by appropriate functionality its access software (this would be suitable via plug-ins to solve in conventional Internet browser programs) born First of all - free of charge - by online query the allocation unit to determine whether and where an ent talking reconstruction file exists, and then the Ser. offering the allocation unit (as a database system) ver either immediately the reconstruction file available for download, or a Hyper link to a corresponding, separate reconstruction server offers. Using the usual identification and Ab calculation processes, e.g. B. by entering credit cards formations, can then transfer the reconstruction file to the user (and thus his possibility on the to access unencrypted document) with the ge desired financial transaction, whereby for this purpose especially with the reconstruction server corresponding function modules are implemented.  

In the context of the invention, the data-based marking (also It is only necessary to implement the signature) dig that a downloadable, encrypted rare electronic document file so clearly electronic is identified that using this signature one too appropriate reconstruction file can be found. equal it is probably best to calculate a sol Chen signature on the basis of otherwise generally known algorithms and the entire file increase that a change in the order of the data hold the file or delete or change or insert of data by corresponding effects on the signature can be determined.

More specifically, there is a preferred way to generate the Signature in it, using a (both on the provider side and also known from the user) algorithm from the data of the File to calculate a parameter, so far this File and its structure, especially the order of the data content, clearly identified. A manipulation on in the file, especially in the order of the data content, would then lead to a (renewed) Be calculate the signature differently from the original original signature would therefore not only be concrete (Encrypted) document files clearly identified can be, but especially changes to it become noticeable.

It is important for the present invention that with Hil Fees of an on-line contact that a user brings down download an encrypted file the allocation unit is made accessible, which then in the manner described the user is shown a path gets how he gets the specifically needed reconstruction can get file. According to training, it is therefore prefers, especially these processes, namely primarily that Registering the signature or querying an assigned one Paths for the reconstruction file to be carried out automatically,  for example through appropriate functionality the plug-in in the internet access and playback software of the user.

According to further training, it is also advantageous in other respects known to be a properly restored Da tei, namely after obtaining a reconstruction file and merging with the encrypted electronics document, with an individualizing electronic watermark so that the possibility tracking of unauthorized disclosure of the recombi document.

The watermark generated can also run with a time stamped. The characteristic of one Watermark is that it is only recognized by the publisher and that there are minimal changes in the Da did not have the character identifying its user loses.

As a result, the present invention offers the possibility a comprehensive system for the protection of authors rights to electronic documents in the electronic Da tennetz, especially on the Internet, which the legitimate interest of the document (content) provider in prevention of abuse and possible compensation reconciles with the interest of (honest) users, the advantages of using the Internet, for example, to quick and easy the full variety of electronic media to be able to.

While so far, in particular from provider or publisher effective control is not possible at all was, by the present invention by the Shifting a responsibility and responsibility for the legal reproduction on the internet units "electronic allocation unit" or "reconstruction  Server unit ", in connection with the user-side, loka len units.

The publisher's responsibility for redistribution ends in accordance with the currently applicable agreements between a publisher and the collecting societies the transfer and the correspondingly agreed ge business accounting of the data between publications onsserver and customer.

In relation to the collecting societies there is then at all the obligation, the number of direct down to prove loads. One to the collecting society Paying fee is based on the number of possible next distributions, generated from statistical data, ge underestimated. In this sense, a current distribution concept with the metaphor of a publisher's toll job.

If, as achieved by the present invention, by or client software for the distributed document must then be established, which then requires a server contact Forces reconstruction of the unencrypted content, then is thus a toll station on the user or client side create the other advantages over a server side gene owns. So, even if no material (Financial) compensation is required by the over carrying information on the signature or free switch server a very precise market, usage and loading usage statistics can be realized. If according to the invention a usage by a user is more accurately registered that can exist for a provider of digita len documents on the Internet only the obligation to a specific use of bound licenses or fees to be paid to a collecting society.  

In addition, new marketing models can be developed where, for example, the use of digital docu ment files by a server or sender in the context of Advertising or for image reasons.

Further advantages, features and details of the invention result from the following description more preferred Exemplary embodiments and based on the single figure; this shows in

Fig. 1 is a schematic block diagram of the device for copy-protected distribution of electronic documents acc. a first, preferred embodiment.

The system shown graphically in FIG. 1 separates a publicly accessible electronic data network, in the present case the world wide web (www) as an Internet system 12 , from a provider 14 , in the present case a provider of electronically, by means of symbolic limitations 10 digital audio documents to be distributed via the network 12 , or by a user 16 , who uses a symbolically shown access unit 18 (usually a computer unit equipped with common Internet access software) in a otherwise known manner to a document server unit accessible via the electronic data network 12 20 accesses can. This takes place on the basis of generally accessible, common Internet protocols, for example TCP-IP, HTTP or FTP, the document server unit 20 for displaying a selection of various electronic documents for an access by means of the station 18 and for the subsequent enabling of downloading ( Download) a selected electronic file is trained.

In this respect, it is common technologies from the State of the art, which require no further explanation.

The documents offered according to the present exemplary embodiment are so-called. Sound or music files which are created in accordance with the MP3 file format and via a suitable playback unit 22 , which is particularly preferably assigned part of the user-side access unit 18 or the water is, can be played (player or viewer as a playback unit; these are suitable for reading the MP3 file format and in turn converting it into sound signals or music; this is also well known from the prior art).

Structurally, the MP3 file format consists of a header as well as a lot of data units (data packets, too Called frames), in which the music data kompri are included. The size and structure of the frames are described in more detail by the header data and therefore exact established. Specifically, each frame compresses a plurality of Audio Access Units (AAU), each of these AAUs for a predetermined period of the audio signal (about 8 or 12 msec). The temporal audio signal is acc. MP3 standard discretely FFT-transformed, the Transfor mation based on 32 specified frequencies is carried out and the data of an FFT transformation in an AAU are stored, as is the usual procedure when generating an MP3 sound file.

According to the present invention, however, an MP3 sound file stored in the document server unit 20 , provided for access by the user 16 and loaded by the provider 14 of the document server unit 20, is encrypted, specifically by means of an encryption unit 24 .

More specifically, the encryption is that the individual frames of the MP3 file structure are interchanged in an order that does not correspond to the original music signal, frames have been removed, additional, meaningless frames have been inserted and / or frames have been exchanged from two or more independent sound files were taken before, with such an encryption manipulation - hereinafter also called semantic encryption - the actual structure of the MP3 format, namely the header and associated frames, was obtained. In other words, the playback unit 22 (like any other MP3 player or viewer unit) will be able to open and play the MP3 file encrypted in this way. Due to the manipulations made, however, the received signal, converted from MP3 into an audio signal and converted back to the user, makes no sense, since the exchanges, exchanges, distances and additions of frames distort the original sound signal in such a way that the original piece of music or similar content the MP3 file is no longer usable for a user.

In an advantageous manner according to the invention, the provider 14 also performs the upload (upload) of an encrypted MP3 file into the document server unit 20 in such a way that not only an encrypted version of the MP3 file is present here, but a large number , for example 1000 or 2000 identical or different encrypted versions of the same piece of music (whereby, as explained, for a user 16 who queries the document server unit 20 with its table of contents or a search engine associated with the files offered, but not explained in more detail, the fact of encryption is not recognizable, since the MP3 format has also been preserved for the encrypted files).

This measure is based on the fact that a majority of the The Internet, for example, offers MP3 music files the document server units are so-called pirate sites, näm Lich such Internet stations, which in one by Ur copyright or similar rights do not entitle providers authorized pieces of music to any, more common instruct free download to any user offer, with traditionally the spread of the Provider created or represented piece of music by this then can no longer be controlled and so far considerable damage occurs.  

Due to the measure described within the scope of the invention, however, such a document server unit as a pirate site is acted upon by a large number of MP3 files, which in the end are not easily usable from the user perspective, so that the probability that a user will receive an unencrypted one (and therefore easily usable) music file loads, is rather small. Already due to this fact, it can be expected that the user, frustrated by the negative result when opening the downloaded, encrypted music file (whose download with current file volumes in the range between 2 and 4 MB for typical pieces of music of popular music) is demotivated and the future use of this document server unit 20 is omitted or is ready to download and install the software component offered to him, with which the signature server unit can then be informed.

A further measure within the scope of the present invention, however, ensures that not only the described effect prevents or at least thins out the further spread of unauthorized music files (and of course also other electronic document files), but also offers the user 16 the opportunity to to convert the encrypted MP3 document downloaded by him from the document server unit 20 into an unencrypted version, so that after steps to be described further below, he becomes a legal user (and from the point of view of the provider 14 potentially revenue-generating):
The provider 14 , who has encrypted his MP3 file in the file described by the encryption unit 24 and loaded it onto the document server unit 20 of the Internet 12 , generates an associated reconstruction file with the encrypted form of the file, ie a file that contains the necessary information Contains instructions to restore the swapped, exchanged or replaced frames of the MP3 file back to their original form. Such a reconstruction file, which is individually associated with an encrypted MP3 file, is uploaded to a reconstruction server unit 26, which is also available on the Internet.

A logical link (and thus the identification and accessibility of the reconstruction file for an MP3 sound file) is achieved by calculating a so-called signature for an encrypted MP3 sound file, i.e. a mathematical algorithm is applied to the encrypted file, and in The result is a signature in the form of a character string or a file that is characteristic of the content and sequence of the content components of the encrypted MP3 file. This signature, calculated by means of a signature unit 28 on the provider side 14, is uploaded to a signature server unit 30 also located on the Internet 12 in such a way that a database unit provided therein, to be queried by the user in the manner of a concordance table, has a (usually a clear) link and Relationship between a signature of an encrypted MP3 document and the name and location (e.g. link) of an associated reconstruction file contains and can create.

On the user side, the local access unit 18 can then make contact with the signature server unit 30 in the electronic data network 12 using one of these functional units 32, preferably embedded in the manner of a plug-in, after a local signature unit 35 , which is also assigned to the access unit 18 ( or embedded in it) with the locally known (general) algorithm that has calculated the signature applicable to a special (encrypted) and downloaded ne MP3 file.

The network access by means of the functional unit 32 then provides the locally calculated signature (by means of unit 35 ) of the signature server unit 30 in the described embodiment, and the user 16 receives a file name and an access address from the signature server unit 30 by means of the concordance tables le stored there (Link) for the reconstruction file associated with the transmitted signature.

With this, the user 16 is then able to generate the unencrypted, that is, from the user's point of view, the version of the musical piece by the playback unit 22 from the encrypted MP3 file available to him, with a reconstruction unit 34 locally for the purpose of decryption is provided, which can also be implemented as a plug-in, and which - in the manner of a reversal of the function of the provider-side encryption unit 24 - cancels the encryption by executing the reconstruction instructions in accordance with the reconstruction file received from the reconstruction server unit.

Usually, however, the download of the reconstruction file from the reconstruction server unit 26 for the purpose of generating an unencrypted local MP3 sound file is linked to the execution of a payment or billing process, ie the user usually pays a predetermined amount of money or the like. that the reconstruction server unit gives him the option of receiving the decision or reconstruction option that matches the encrypted MP3 file before him in the manner specified by the signature server unit. For this purpose, in an otherwise known manner, the user has an identification or billing unit 36 which, in particular also as a functionality of the access unit 18 , provides a billing identification unit 38 assigned to the reconstruction server unit 26 so that user data is available. that the reconstruction server unit 26 and the associated billing / identification unit 38 identify the user, for example his credit card number or the like. Payment modalities can be recorded and a corresponding payment can be booked or can be booked or offset against an existing credit.

In the manner described, the invention can underlying goal of curbing an unauthorized Dissemination of electronic files effectively achieved become: Not only is the (massive) charging more key and therefore not for users as such usable MP3 files (without this, however, without downloading and playing would be recognizable) considerable che uncertainty and frustration, which at multiple fa chem failure user surely from further access to a relevant document server unit (pirate site) should hold, but beyond that the user gets the possibility, preferably by means of a billing process decrypt the loaded file and thus again to make it usable.

While the present embodiment is based on MP3 Music files related, is the present invention not limited to this file format, but in principle ell any electronic file format of an electronic, vulnerable document that gives the opportunity to semantic encryption of the kind described above bie tet is suitable for use in the present invention.

However, due to the commercial potential of openable MP3 the special problem to be expected, more massive Damage caused by illegal distribution, so this exec example was chosen.

Supplementary to semantic encryption is in particular of the MP3 format still explains that by the fact that the frames are independent of each other, without them others can be exchanged. One can be advantageous such a change is not mechanically or algorithmically determined be put. Alternatively, a change in Hea the complete illegibility of the MP3 document to lead; however, due to multiple header entries  under certain circumstances here the possibility of a changed Identify and correct headers.

MP3 also offers the option of decompressing the Frames within the same swap the AAU, or FFT factors can be changed so that a certain played audio frequency changes drastically. Also offer MP3 the possibility of audio files in the by the AAU set time interval to exchange or run in parallel, so that two or more sound signals in parallel, possibly in the same ben file. A corresponding recon structuring instruction (an associated reconstruction file tei) could then look like that from egg In such a file, only the data that can be identified with a specific audio signal.

In general, however, as explained, the seman principle applies table encryption also beyond the MP3 format and for further document data structures, whereby in particular offers the semantic encryption opera on an object level of a respective file structure door formats.

The present invention also offers the possibility, by appropriate design of the user or access-side functional components, to further increase control over any illegal document files or to create the origins of illegally obtained documents: it is particularly preferred to use the functions unit 32 so that it automatically carries out a selection or access process to the Internet signature server unit 30 after the download of an (arbitrary) MP3 file and this transmits the locally calculated (unit 35 ) signature of the respective MP3 file; if the MP3 file has been the subject of an online contact with a document server unit 20 that has just been carried out, a path (indicating the link) could also be transmitted in parallel with the transmission of the signature to the signature server unit, indicating that from which address the relevant MP3 file comes.

In particular, the determination means for the signature server unit 30 that this is an unknown signature could then trigger further processing steps, such as, for example, following up on a potentially illegally received (or possibly not encrypted) file.

In addition, the unit 32 can be designed such that it also detects the names and addresses of the servers (by means of Internet trace trace technologies) that were used for the transmission of the data as part of the determination of the source of the data. In this way, a profile can be generated, which can be used to save those document servers, e.g. B. could not be penetrated by the encrypted documents, but which have been recognized by the statistics on the signature server as particularly dangerous and comprehensive pirate sites, to be examined more closely. The information found in this way can then be used to provide evidence and be used when switching off the service from the content providers or when specifically filtering out the requests directed to these sites from the network providers.

While, as shown in FIG. 1, signature server unit 30 and reconstruction server unit 26 are basically (spatially) separate units on the Internet, in particular it is also provided that a (central) signature server unit provides information on a plurality of different ones Re construction server units, it is also possible in particular that a provider integrates the signature server unit and reconstruction server unit, insofar as the signature server unit already receives a suitable, related construction file when a corresponding user request is received (if necessary after the financial transaction) can be sent to the user.

As a result, the invention effectively achieves that Organization system for ver over an electronic data network shared electronic documents is created which the Interests of the legitimate provider of the documents clearly better considered than this with the conventional, un controlled and uncontrollable spread of Da is the case. The present is particularly relevant Invention for pieces of music, because the music industry sees in the free, uncontrolled distribution of MP3 data the internet is an existential threat to your business survival. Those favored by the music industry new music formats, on the other hand, have added Si Security technology and access technology no additional Advantages for the user. The biggest disadvantage is rather, in that the files protected in this way he easily are recognizable and in direct comparison to MP3 files exhibit parts in usability, so that when the user decides which file to download the protected file data is avoided likely. This decision of the user is thereby it favors that it is clear to the user and before the down load can detect what is an unprotected file and what is a protected file.

The object of the invention as set forth was not in the complete suppression of illegal use proprietary data. Rather, there is the Inten tion of the invention therein, the attitude of the user to change the use of easy to download the data is questioned and a reliable (and not further questioned) use of data of unclear origin is always to be questioned.

Claims (15)

1. Device for copy-protected distribution of electronic documents in a publicly accessible electronic data network ( 10 )
one with the electronic data network ( 10 ) ver, a user ( 16 ) assigned to the access unit ( 18 ), which is designed to carry out a charging access and to open a loaded electronic document by means of a playback unit ( 22 ),
and a document server unit ( 20 ), which is designed to enable loading access via the electronic data network ( 10 ) to a selected one of a plurality of documents offered by the document server unit ( 20 ),
wherein the electronic document has a document data structure that contains document data,
a document provider ( 14 ) connected to the electronic data network ( 10 ) is assigned an electronic encryption unit ( 24 ) for generating an encrypted form of an electronic document as well as for generating an associated reconstruction file, where the encrypted form is characterized by that the electronic document in the encrypted form is not usable in the intended manner for the user ( 16 ) and the presence of an encryption of the electronic document cannot be recognized automatically from the document data structure without checking the content of the document,
the document data provider ( 14 ) is assigned an electronic signature unit ( 28 ) for identifying an encrypted document by means of a data signature, the signature being formed such that it enables a reconstruction file to be associated with an associated encrypted form of the electronic document,
a reconstruction server unit ( 26 ) is connected to the electronic data network and is designed to store a plurality of reconstruction files and enables the access unit ( 18 ) of the user to load access to a selected reconstruction file,
a connection to a reconstruction file to be selected can be established by means of an electronic allocation unit ( 30 ), to which the access unit ( 18 ) of the user and a user-associated signature unit ( 35 ) associated therewith by transmitting the data-related signature associated with an encrypted document rarely the electronic data network ( 10 ) can be accessed,
the access unit ( 18 ) is designed to carry out a loading access to the reconstruction file by the reconstruction server unit ( 26 )
and the access unit ( 18 ) is assigned a local reconstruction unit ( 34 ) which is an encrypted form of an electronic document loaded via the electronic data network ( 10 ) with an associated one, via the electronic data network ( 10 ) from the reconstruction server unit ( 26 ) merges the loaded reconstruction file and creates an electronic document in a user-friendly, unencrypted form. 2. Device according to claim 1, characterized in that the electronic encryption unit ( 24 ) is designed such that the operations can be performed to encrypt an electronic document on data packets of the document data structure:
Exchanging and / or removing a data packet and / or adding a data packet to a predetermined position in a sequence of data packets and / or exchanging a data packet for a data packet that is preferably not contained in the original electronic document, in particular by means of a computer access to the respective one Data packets of the document data structure associated electronic memory areas of the electronic encryption unit. 3. Device according to claim 2, characterized in that the electronic encryption unit ( 24 ) is designed to generate the reconstruction file with information about the exchanged, removed, added and / or exchanged data packets. 4. Device according to one of claims 1 to 3, characterized in that the electronic assignment unit ( 30 ) is a with the electronic data network ( 10 ) verbun dener database server, which forms a common server unit with the reconstruction server unit ( 26 ), or which is spatially separated from the reconstruction server unit ( 26 ) and in particular enables the connection and / or connection establishment for a plurality of different reconstruction server units. 5. Device according to one of claims 1 to 4, characterized by a user identification and / or accounting unit ( 38 ) assigned to the reconstruction server unit, which is used to record data individualizing a user, to carry out a financial transaction with the user and / or is designed to assign or manage user-specific or user-group-specific access rights. 6. Device according to one of claims 1 to 5, characterized in that the user-side and the electronic signature unit ( 35 , 28 ) for performing a algorithm based on a algorithm common to the signature units reading operation be determined data positions of the encrypted document to generate the data signature is trained. 7. Device according to one of claims 1 to 6, characterized characterized that the electronic document is a Audio and / or video and / or animation and / or Simulation and / or program file is. 8. Device according to one of claims 1 to 7, characterized characterized that the document data structure from the Group is selected that supports the data formats MP3, MPEG, XML has. 9. Device according to one of claims 1 to 8, characterized in that the access unit ( 18 ) and / or the playback unit ( 22 ), preferably by means of an embedded in this functional unit ( 32 ) for performing automatic access to the assignment unit ( 30 ) after a loading access to an electronic document from the document server unit ( 20 ) is formed, further preferably the function unit ( 32 ) is designed to transmit a link or path information associated with a document relating to its source for function maintenance. 10. The device according to one of claims 1 to 9, characterized in that the assignment unit ( 30 ) has means for detecting user accesses with a reconstruction file not assignable or a non-existent data signature. 11. The device according to any one of claims 1 to 10, characterized in that the local reconstruction unit ( 34 ) means for generating an individualized data-like identifier, in particular an electronic watermark, rarely has a document on the generated unencrypted document, preferably the individualized data-related identifier corresponds to the data-based marking of the corresponding encrypted document. 12. The device according to one of claims 1 to 11, characterized characterized that the local reconstruction unit Means to enable or prevent a local Save an unencrypted document points, preferably depending on by the Rekon control server unit received control data.   13. A method for copy-protected distribution of electronic documents in a publicly accessible electronic data network ( 10 ), in particular for operating the device according to one of claims 1 to 12, characterized by the steps:

• - Generate an encrypted form of an electronic document and an associated reconstruction file by a document provider ( 14 ), where the encrypted form is characterized in that the electronic document in the encrypted form for the user ( 16 ) is not usable in the intended manner and the presence of an encryption of an electronic document cannot be recognized automatically from the document data structure without checking the content of the document,
• - storing the encrypted document by the document provider ( 14 ) in a document server unit ( 20 ) which is publicly accessible via the electronic data network,
• - Storage of the reconstruction file by the document provider ( 14 ) in a reconstruction server unit ( 26 ) which is publicly accessible via the electronic data network ( 10 ),
• Calculating a data-based signature based on the encrypted form of the electronic document by the document provider, which is formed in such a way that it associates a reconstruction file with an associated encrypted form of the electronic document,
• - Entering the data signature by the document provider ( 14 ) in a via the electronic data network ( 10 ) can be queried allocation unit ( 30 ), which is a connection to an associated reconstruction file in response to user access while transmitting an encrypted document assigned to the data Produces signature,
• - Access by a user ( 16 ) to an encrypted document in the document server unit ( 20 ) and performing a loading process of the encrypted document to a local playback unit ( 22 ) of the user ( 16 ),
• - Queries of the assignment unit ( 30 ) by means of an access unit ( 18 ) assigned to the user, connection establishment and access to the reconstruction file and
• - Creating the unencrypted file at the user ( 16 ).

14. The method according to claim 13, characterized in that the step of storing the encrypted document in the document server unit ( 20 ) comprises storing a plurality of encrypted document versions of the same unencrypted electronic document. 15. The method according to claim 13 or 14, characterized by locally saving the manufactured non encrypted the document with a data-related indivi dualization in the manner of an electronic water ampersand.