EP1081884A2 - Method for transmitting encrypted data via a broadcast network, where the decryption data is obtained through a bidirectional communication link - Google Patents

Abstract

The method involves the user requesting decoding data with a duplex transmission method, esp. a mobile radio or telephone connection by selecting a data service provider, the provider transmitting decoding data to the user via the duplex transmission method and the user decoding the encoded data using the decoding data.

Description

State of the art

The invention is based on a method for transmission of encrypted data or according to the genus of independent claim.

Digital Audio Broadcasting", Eureka - 147 Project, April 1996 bekannt, daß bei DAB (Digital Audio Broadcasting) Programme und/oder Daten für einen bestimmten Empfängerkreis ausgestrahlt werden können. Diese Betriebsart wird mit dem englisch sprachigen Begriff conditional access bezeichnet, also einem privilegierten Zugang zu diesen Programmen und/oder Daten. Dafür sind diese Programme und/oder Daten verschlüsselt, wobei die berechtigten Empfänger entweder einen Schlüssel mitübertragen bekommen, um die Programme zu entschlüsseln, oder eine Speichermöglichkeit an ihrem Empfänger aufweisen, wie z.B. eine Smartcard, die zumindest die Daten enthält, um einen Schlüssel zu entschlüsseln oder um sogar das ganze Programm und/oder die Daten zu entschlüsseln. Eine Smartcard weist einen Mikroprozessor auf, der Informationen speichert, verarbeitet und verwaltet. Mittels einer Geheimnummer und/oder Verschlüsselungstechniken sind einer Smartcard ein hohes Maß an Sicherheit hinzugefügt. It's already out of the brochure

Digital Audio Broadcasting ", Eureka-147 Project, April 1996, known that programs and / or data for a specific group of receivers can be broadcast with DAB (Digital Audio Broadcasting). This mode of operation is designated by the English term conditional access, ie a privileged one Access to these programs and / or data For this purpose, these programs and / or data are encrypted, the authorized recipients either being given a key to decrypt the programs, or have a storage option on their recipient, such as a smart card, at least which contains data in order to decrypt a key or even to decrypt the entire program and / or the data. A smart card has a microprocessor which stores, processes and manages information. A smart card is high by means of a secret number and / or encryption techniques Added level of security t.

Is the access authorization using the smart card time-limited, the customer will be expired obtain a smart card that is still valid or extend the validity of your smart card.

Advantages of the invention

The inventive method with the features of In contrast, independent patent claims have the advantage that the key to decrypt the encrypted Programs and / or data using a Broadcasting procedures such as DAB are broadcast, by means of a duplex transmission method, e.g. on Mobile radio transmission method is transmitted so that the User can decrypt the received data. This is the user is able to access the necessary keys to decrypt the to obtain encrypted data. He wins with it great degree of flexibility. In addition, the Users to just get the necessary key if he has the encrypted programs and / or data actually want to receive.

In addition, it is advantageous that the invention is based on already uses existing infrastructure, because both a broadcast distribution system as well as various Mobile radio systems are already installed and can be used become.

Another advantage is that the duplex transmission method a record of a user is transmitted and that by means of Broadcasting system then continuously updated Additional data are transmitted using this record be used. This makes it possible for a user to only once using a duplex transmission method receives it and then by means of the additional data that about a Broadcast transmission system are being updated. This method of updating is for both Data service providers as well as extremely for the customer inexpensive.

By those listed in the dependent claims Measures are advantageous training and Improvements in the independent claims specified procedures possible.

It is particularly advantageous that the user when he the decrypt encrypted data or if he wants one Want to load the data record using the duplex transmission method selects the data provider and yourself either the key or the record of that Data service provider loads. This means that the user is completely free to determine when, where and what he will use for data services would like to. It should be noted that such data services and encrypted data from different Data service providers are offered so that the user is on an opportunity base that he desires Select data service provider.

It is also advantageous that both the key and also the data set that the user can access using the Duplex transmission method loads, a time-limited Is valid. This makes it for the data service provider possible its data service for a certain time offer and calculate. It is also the user transparent how long the data service he wants is available to him.

In addition, it is advantageous that the Data service provider the user the transmission time for the Decryption data and / or the data set calculated, so that the user has a corresponding one for the period of validity Amount for the transmission time of this necessary data in order to use the data service paid. Then this is a very simple billing system for a data service provider, because by the amount that he is for the transmission time of the Key or record requests, at the same time rented out his data service. In addition, this is Billing system also for users of large Transparency, because he can, for example, if he uses a cellular network, the cost of the Data service can take.

drawing

Embodiments of the invention are in the drawing shown and in the following description explained. FIG. 1 shows a method for transmission of encrypted data and Figure 2 shows a method for Transfer of records.

Description of the embodiments

By introducing digital Broadcast transmission methods such as DAB are attractive Given opportunities to provide data services through the Broadcast distribution network to transmit.

DAB is a digital broadcasting process that is particularly suitable for mobile reception. By the Use of the so-called orthogonal frequency division multiplex in particular a frequency selective attenuation in their Effect on the transmitted signal greatly reduced. The Signal generated by means of orthogonal frequency division multiplexing is transmitted at DAB on the transmission side to several Frequencies distributed, with the signal components on the different frequencies do not affect each other. This behavior is described as orthogonal. Thereby it is achieved that a frequency-selective attenuation only Signal component disturbs that on the frequency that one is subject to strong damping, is transmitted.

In addition, the signal in the transmitter is one Channel coding subjected to the original data additional data are added so that errors in the Recipients using this additional data can be corrected. DAB also has the property that besides the audio data also other data at the same time be transferred, the size and division of this Data can be freely designed. DAB has a frame structure which has frame fields by means of which a receiver recognizes which content is transmitted in the respective frame becomes. For example, there is a frame Information that from a particular data service provider Data for a navigation system included in this frame are. If the recipient searches for this data, the recipient evaluates Recipients choose this frame to get the data.

But also other digital broadcasting and Television transmission methods, such as DVB (digital video Broadcasting) or DRM (Digital Radio Monial) offer the Possibility to transfer data. This Transmission methods also have the orthogonal Frequency division multiplex, they differ from DAB especially by the transmission frequency range, the Frame structure and the transmission bandwidth.

Digital cellular cellular transmission methods such as GSM (Global System for Mobile Communication) or UMTS (Universal Mobile Telecommunication System) have in Comparison to the broadcasting method Property that connects to specific users is produced and not an entire area is served, without the individual users in this area directly to select. So users have to dial directly here be while in a broadcast transmission process every switched on receiver receives the data.

When the distribution of a data service becomes the combination a broadcast transmission method and a duplex transmission method, like it Cellular transmission methods are used, so result yourself advantageous ways to set up a data service only to make it available to a certain group of users.

Duplex transmission methods have the property that Data is transmitted in both directions, i.e. that communicating stations both transmitters and Are recipients. Telephone and cellular connections are Examples of this.

Broadcast transmission methods, on the other hand, are simplex transmission methods, since only one station sends and many received other stations. With some Radio transmission systems become a so-called half duplex used, i.e. if one station transmits, the other can Station only received while using a duplex transmission method send both stations simultaneously can.

If a data service is used only by a certain group of recipients made accessible with encryption reached. Encryption is used here in a way performed so that the data with pseudo-random numbers can be combined, these pseudo-random numbers with a pseudo-random generator and where this pseudo-random generator with one Initialization word by a random number generator is generated, initialized. Is a random number generator for example a noise generator that uses random numbers can be generated.

Otherwise, other types of encryption are conceivable, too counts for example the scrambling of data structures.

Alternatively, a large number can be generated once Random numbers are stored in a memory at Need for initialization of the pseudo random generator to be used.

Pseudo-random numbers have the property that if one knows the initialization word, all subsequent pseudo-random numbers can be calculated because the Calculation rule with which the pseudo random generator generates the Generate pseudo random numbers known to the recipient. Around ie data encrypted with pseudo-random numbers have been decrypted, it is necessary that the Initialization word is known in the receiver. So it serves as a key. Then the receiver can use a pseudo-random generator generate the same pseudo-random numbers and by further linking these pseudo-random words with the encrypted data this data decrypt again.

If you link the data with the pseudo-random words in the transmitter using an exclusive-or link, then one decrypts the data in the receiver by another one Exclusive OR combination of the encrypted data word with the same pseudo-random number. Because, a number becomes x1 twice with another number x2 exclusive-or-linked, the result is the original number x1.

In Figure 1 is a method for the transmission of encrypted data shown as a flow chart. In Process step 1 starts the process. In Method step 2 selects a user using a duplex transmission method a data service provider to help from a key to a data service provider Request decryption of the encrypted data.

In method step 3, the data service provider by means of the duplex transmission method the key to Decryption of the encrypted data with a Broadcast transmission system are sent, transmitted. There is a transceiver station for a duplex transmission method connected to a radio receiver, so that a data transfer from the transmitting / receiving station to Radio receiver is possible. So the key is from received by the transceiver and sent to the Hand over the radio receiver so that the radio receiver the can decrypt encrypted data.

The user chooses the data service provider by direct Inputs on his radio receiver, or the Broadcast receiver has a list of different ones Saved data service providers from which the user selects a data service provider and the radio receiver then automatically this data service provider using the Sending / receiving station selected.

In method step 4, the user receives using a Broadcast receiver the encrypted broadcast data. In Method step 5 the user decrypts using his Key the received encrypted data in the Radio receiver.

In step 6, the user provides the decrypted Data using acoustic and / or optical means for Representation in order to view or read them. The data is e.g. used in a navigation system to to display the current traffic situation on a display in order to the fastest possible route for a driver to calculate his goal and to give the driver his own to show the optimal way to his goal.

Other options are that the user is current Selects stock market data or that a user encrypted himself Listens to radio programs or that e.g. a construction company transmits certain data to a building site or that the police with such a procedure important data from databases to their location. The grants Encryption that only the authorized participants with the Key that can decrypt data. Is a high one For example, security as required by the police becomes necessary additionally a smart card is used to hold the key for decryption using a duplex transmission method to be able to receive.

In step 7 it is checked whether the key is still there is valid, with a key for a predetermined time Is valid, i.e. the user checks using his Radio receiver, whether the time has already been reached which of the keys loses its validity. For that points the radio receiver has a chronometer. Is the Keys still valid, are again in step 4 receive encrypted data. The key is no longer valid, it is checked in step 8 whether the user is still interested in this data service. This expresses the User by input on his radio receiver. Is this the case is in process step 2 again via the Duplex transmission method of data service providers selected to get a new key, the Radio receiver the connected transceiver station activated with which the data service provider is dialed. If the user is no longer interested in this data service use, the method is ended in method step 9.

The GSM transmission method is used here as a duplex transmission method used and as Broadcasting procedure DAB. For this purpose, a GSM send / receive station integrated in a DAB receiver or connected. The DAB receiver then receives from the GSM transceiver the key he used to Decryption of the encrypted data received used. Alternatively, a can be used as the transmitting / receiving station Operate modem that is connected to the telephone network if the radio receiver is not mobile.

FIG. 2 shows a further development of the invention Process for the transfer of data sets as a flow chart shown.

The method is started in method step 20. In Method step 21 requests a user via a duplex transmission system a record of one Data service provider. The user either chooses again directly to the respective data service provider, or the user selects one in the radio receiver stored list a data service provider on what the radio receiver by means of a connected transmitting / receiving station the selected data service provider selects to load the data set.

In method step 22, the user receives the Duplex transmission method the requested record from the data service provider, the data record using the Transceiver station is received and then to the connected radio receiver is transmitted.

In method step 23, the user uses the received one Record the data with acoustic and / or means optical representation that the radio receiver has, to represent. With this e.g. a navigation system initialized, whereby in addition to the distance data now current traffic data are added to a to determine the optimal way to a goal.

In method step 24, the user receives using his Broadcast receiver encrypted additional data with which the User in step 25 his data set updated. So the navigation system always has the current traffic data. For example, the Existence of a traffic jam can be recognized with the original record would not have been recognized. To the enable privileged access to this additional data, are decryption data in the original record included with which the encrypted additional data can be decrypted.

In method step 26 it is determined whether the data record is still valid, i.e. a record that the user of the Data service provider receives only one in time given validity. This is the radio receiver by means of a chronometer, which the radio receiver having. This enables the data service provider to: sell its data service on an opportunity basis can without having to have a fixed customer base. The is a method currently used by telephone companies (Call-by-Call) and Internet access providers (Internet-by-Call) to offer.

The customer pays by transferring the original Record for the given time, how long it the Can use data service. This is done by the Data service providers have a specific price for that Transmission via the duplex transmission system. At a duplex transmission method as it is a Is cellular transmission process, this happens through Determination of telephone charges. This also means the price which the customer has to pay for the data service to the customer fully transparent.

If it is now determined in step 26 that the Data record is still valid, then in step 24 continued to receive additional data to the original record continues to be up to date hold. If the data record is no longer valid, in Method step 27 checks whether the user has a new one Wishes to load record from data service provider, where the user now also selects a new data service provider can choose. If this is the case, then in Method step 21 by the user via the duplex transmission system a new data set using the transceiver station requested. If the user is not interested more on this data record, then in method step 28 the proceedings ended.

Again, the GSM mobile radio system for the Duplex transmission method used and the DAB broadcast transmission method for the distribution of Additional data.

This method is particularly suitable for Navigation systems. About the duplex transmission method the user loads a data record, the current one Traffic data. Via a broadcast transmission system then continuously updated data is received to the Renew data set for the navigation system.

Alternatively, however, other combinations are possible with which a duplex method with a Broadcast transmission method is used. Is the customer in a place where a connector to the wired Such a telephone connection can exist as a telephone network Duplex transmission methods are used to either the key to decrypt the encrypted data to receive or to receive the record.

In addition to the digital broadcasting broadcasting procedures are also analog broadcasting method for the transmission of Data suitable if, for example, an additional digital Signal for the transmission of data with the analog Broadcast signals is transmitted. The well-known radio data System is an example of this.

Claims (7)

Procedure for the transmission of encrypted data, the encrypted data using a Broadcasting process to be transmitted to users (4), characterized in that decryption data by means of a duplex transmission method, in particular a cellular or telephone connection from a user be requested by selecting a data service provider (2) that the decryption data from the data service provider to the user using the duplex transmission method are transmitted (3) and that with the decryption data by the user using the broadcast transmission method received encrypted data are decrypted (5). A method according to claim 1, characterized in that the decryption data for a predetermined time Decryption of the encrypted data can be used. A method according to claim 1 or 2, characterized in that that the respective user transmission time for the Transmission of the decryption data in the duplex transmission method is billed so that thus the provision of the encrypted data and the Decryption data is paid. The method of claim 1, 2 or 3, characterized characterized that records by means of the duplex transmission method transferred to a respective user are (22) that current, encrypted additional data by means of the broadcast transmission process to the users are transmitted (25) that the encrypted additional data by means of decryption data that the data records have, are decrypted and that the decrypted additional data can be used by the user together with the data records (25). A method according to claim 4, characterized in that the data records are requested by the respective user (21). A method according to claim 5, characterized in that the data sets are used by the users for a predetermined time (26), followed by a new data record by means of the duplex transmission method from the user is requested and received. A method according to claim 6, characterized in that the transmission time for the transmission of the data records the duplex transmission method to the respective user Bill is made so that the records and the Additional data are paid for by the respective user.

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