ARRANGEMENT FOR INDEPENDENTLY REQUESTING A PLAYING AUTHORIZATION FOR A REPRODUCED ENCRYPTED INFORMATION SIGNAL

Abstract: An arrangement (1) for verifying a playing authorization for an encrypted information signal (I) reproduced by means of a reproducing device (2, 3) and for supplying a decrypted information signal (I) when a playing authorization is available, comprises verification means (19) for verifying a playing authorization for a reproduced encrypted information signal (I), and comprises decryption means (32) fro decrypting a reproduced encrypted information signal (I) when a playing authorization is available, and comprises interrogation means (43, 35) for independently requesting a playing authorization, which interrogation means include communication means (43) which, in the absence of a playing authorization for a reproduced encrypted information signal (I) are capable of setting up a data link (49, 52, 56, 59) and of supplying playing authorization request information to a playing authorization allocation device (51, 53, 57, 60) via the data link (49, 52, 56, 59) and of receiving a playing authorization for the reproduced encrypted information signal (I) from the playing authorization allocation device (51, 53, 57, 60).

Description: Arrangement for independently requesting a playing authorization for a reproduced encrypted information signal. The invention relates to an arrangement for verifying a playing authorization for a reproduced encrypted information signal - which is reproduced by means of a reproducing device adapted to cooperate with the arrangement - and for supplying a decrypted information signal when a playing authorization is available, comprising verification means arranged to receive a reproduced encrypted information signal and adapted to supply key information suitable for correctly decrypting the reproduced encrypted information signal when a playing authorization is available, and decryption means arranged to receive key information and adapted to decrypt the reproduced encrypted information signal when suitable key information is available. Such an arrangement of the type defined in the opening paragraph is known, for example from the document WO 96/05700 Al. In the known arrangement, which is formed by a so-called set-top box, the verification means enable identification information contained in a reproduced encrypted information signal to be determined. When such identification information is present a playing authorization for the reproduced encrypted information signal is obtained. The identification information contains the key information which can be supplied to the decrypting means in order to decrypt the reproduced encrypted information signal. A reproduced deccrypted information signal can be displayed by means of a television set which can be connected to the known arrangement. The known arrangement is adapted to record characteristic playing information which characterizes the number and length of playing events of a deccrypted information signal in the case of a playing authorization. Furthermore, by means of a data link the known arrangement is connected to a broadcasting station which forms a play interrogation device. By interrogating the characteristic playing information recorded by means of the known arrangement the play interrogation device can determine how many times and for how long an encrypted paid-service information signal reproduced by the playing device has been encrypted in the known arrangement and has consequently been used by the user of the known arrangement. Charging for the usually repeated reproduction of paid-service information signals can be effected on the basis of the characteristic playing information. However, with regard the known arrangement it has appeared that the presence of encrypted identification information in the reproduced encrypted information signal, which information allows a correct decrypting of an encrypted information signal and is necessary for the correct operation of the known arrangement, was used by unauthorized persons for making illegal copies which contain the information signal that has already been decrypted. Record carriers with decrypted information signals were sold by persons not authorized to do so, resulting in substantial financial damage for broadcasting stations. Moreover, when the characteristic playing information recorded with the known arrangement is interrogated by means of a play interrogation device the problem arises that a play interrogation device initially has no information whether and where there is a known arrangement by means of which paid-service information signals for which the collection of charges is effected by means of the play interrogation device are reproduced. This considerably complicates the collection of charges for the reproduction of paid-service information signals. Furthermore, it is not possible to rule out that the characteristic playing information recorded by the known arrangement is changed by a person not authorized to do so, which additionally complicates the collection of charges. Moreover, with regard to the known arrangement it has been found that, on the one hand, interrogating the characteristic playing information recorded by means of the known arrangement at comparatively long time intervals will result in uncertainty for the user of the known arrangement as to the amount of the charges and, on the other hand, interrogating the characteristic playing information recorded by means of the known arrangement at comparatively short time intervals will result in a comparatively large expense for the broadcasting station. It is an object of the invention to preclude the problems mentioned above and to provide an improved arrangement of the type defined in the opening paragraph, by means of which, on the one hand, manipulation in determining the charges for the reproduction of paid-service information signals is substantially precluded but, on the other hand, a high flexibility and a low cost in determining the charges can be obtained for a broadcasting station. According to the invention, this object is achieved in an arrangement of the type defined in the opening paragraph in that the arrangement is equipped with interrogation means for independently requesting a playing authorization. Thus, it is achieved in a simple manner that by means of the arrangement in accordance with the invention an independent request for a playing authorization is possible, when required. Upon reception of key information on which a playing authorization is based a reproduced encrypted information signal can be decrypted by means of the arrangement in accordance with the invention. Manipulation by an unauthorized person is then ruled out almost completely because characteristic billing information is generated exclusively in the playing authorization allocation device upon reception of playing authorization request information. Furthermore, charging of the fees to the user of the arrangement in accordance with the invention can be effected at comparatively short time intervals and with a particularly low expenditure for the playing authorization allocation device. In an arrangement in accordance with the invention having the characteristic features defined in Claim 1 it has proved to be advantageous if, in addition, the measures defined in Claim 2 are taken. In practice, it has proved that such an embodiment is particularly reliable and simple and can be realized at comparatively low cost. In an arrangement in accordance with the invention having the characteristic features defined in Claim 2 it has proved to be advantageous if, in addition, the measures defined in Claim 3 are taken. In this way, it is achieved that playing authorization request information for a given paid-service information signal can be supplied to the playing authorization allocation device, which is capable of allocating a playing authorization for this given paid-service information signal. Moreover, the key information, which is necessary for decrypting the reproduced encrypted information signal and which is transmitted to the arrangement upon reception of the playing authorization, is stored only in the playing authorization allocation device identified by the enable information. In an arrangement in accordance with the invention having the characteristic features defined in Claim 3 it has proved to be advantageous if, in addition, the measures defined in Claim 4 are taken. This has the advantage that encrypted information signals transmitted by a broadcasting station and received by the arrangement in accordance with the invention, which signals contain enable information identifying a playing authorization allocation device enabled to allocate a playing authorization, can be supplied to a recording and reproducing device for recording the encrypted information signal. As a result of this, determining the charges for the reproduction of paid-service information signals from a pluarility of broadcasting stations can be effected by means of only one playing authorization allocation device. In an arrangement in accordance with the invention having the characteristic features defined in Claim 3 it has further proved to be advantageous if, in addition, the measures defined in Claim 5 are taken. This has the advantage that the connection set-up information of a plurality of playing authorization allocation devices can be stored and that playing authorization request information can be supplied to a playing authorization allocation device via the data link in a particularly simple manner and with only a very small time delay. In an arrangement in accordance with the invention having the characteristic features defined in Claim 2 it has proved to be advantageous if, in addition, the measures defined in Claim 6 are taken. This has the advantage that on the basis of the playing authorization request information a playing authorization allocation device can detect which paid-service information signal the user of the arrangement wishes to play. As a result of this, determining the charges is possible is in a particularly flexible manner. It is to be noted that the measures defined in Claim 6 can also be applied advantageously in arrangements in accordance with the invention having the characteristic features defined in Claims 3, 4 and 5. In an arrangement in accordance with the invention having the characteristic features defined in Claim 2 it has proved to be advantageous if, in addition, the measures defined in Claim 7 are taken. This has the advantage that the presence or absence of a playing authorization for a reproduced paid-service information signal can be detected in a particularly simple manner. It is to be noted that the measures defined in Claim 7 can also be applied advantageously in arrangements in accordance with the invention having the characteristic features defined in Claims 3, 4, 5 and 6. In an arrangement in accordance with the invention having the characteristic features defined in Claim 2 it has proved to be advantageous if, in addition, the measures defined in Claim 8 are taken. As a result of the provision of key information composed of first key information and second key information a particularly high degree of protection against manipulation by unauthorized persons can be achieved with the arrangement in accordance with the invention. Such encrypting systems are used, for example, during transmission in accordance with the Digital Video Broadcasting Standard. It is to be noted that the measures defined in Claim 8 can also be applied to the arrangements in accordance with the invention having the characteristic features defined in Claims 3, 4, 5, 6 and 7. In an arrangement in accordance with the invention having the characteristic features defined in Claim 1 it has proved to be advantageous if, in addition, the measures defined in Claim 9 are taken. This has the advntage that the reproduction of a paid- service information signal is interrupted until a playing authorization from a playing authorization allocation device appears and the user of the arrangement consequently does not skip a part of the paid-service information signal during the reproduction of this signal. It is to be noted that the measures defined in Claim 8 can also be applied to the arrangements in accordance with the invention having the characteristic features defined in Claims 2, 3, 4, 5, 6, 7 and 8. The afore-mentioned aspects as well as further aspects of the invention will be apparent from the embodiment described hereinafter by way of example and will be elucidated on the basis of this embodiment. The invention will now be described in more detail with reference to the embodiment shown in the drawing and given by way of example, but to which the invention is not limited. Figure 1 shows a diagrammatic representation in the form of a block diagram of an arrangement in accordance with the invention to which an encrypted paid- service information signal can be applied and which is constructed for independently requesting a playing authorization for the information signal in the absence of such a playing authorization. Figure 1 shows an arrangement 1 formed by a so-called set-top box constructed to verify a playing authorization for a paid-service information signal I reproduced by means of a reproducing device, which information signal is available at a charge and is therefore encrypted. An information signal I can be reproduced, for example, by a DVHS video recorder 2, which forms a recording and reproducing device, or by a DVD apparatus 3, which forms a reproducing device. When a playing authorization exists the arrangement 1 is adapted to supply a decrypted information signal I to a TV set 4. A playing authorization can be given by the fact that an information signal reproduced by the reproducing device is not encrypted. A playing authorization for a reproduced encrypted paid-service information signal I is given by the presence of key information S suitable for sucessfully decrypting the encrypted information signal I. Suitable key information S can be stored in the arrangement 1 or can be received by playing authorization allocation means 5, which include one or more playing authorization allocation devices, which will be described in greater detail hereinafter. The DVHS video recorder 2 comprises entry means 6, which include a play button 7 and a record button 8. By actuating the play button 7 the DVHS video recorder 2 can be set to a play mode in which, in a generally known manner, the DVHS video recorder 2 is adapted to reproduce digital information signals I recorded on a magnetic tape 9 in accordance with the DVHS standard. Reproduced information signals I can be applied to first interface means 11 via an operating connection 10. The first interface means 11 are then adapted to transmit information signals I and control signals ST via a generally known data bus in accordance with the bus standard IEEE 1394. Information signals I reproduced in the play mode can be supplied from the first interface means 11 to second interface means 13 of the arrangement 1 via a bus connection 12. The DVD apparatus 3 comprises entry means 14 which include a play button 15. By actuating the play button 15 the DVD apparatus 3 can be set to a play mode in which, in a generally known manner, the DVD apparatus 3 is adapted to reproduce digital information signals I recorded on a a Digital Versatile Disc (DVD) in accordance with the DVD standard. In the play maode reproduced information signals I can be applied to the second interface means 13 of the arrangement 1 via an operating connection 17, third interface means 18 of the DVD apparatus 3 and the bus connection 12. The arrangement 1 comprises verification means 19 having an information signal input 20 arranged to receive a reproduced encrypted information signal I from the second interface means 13. The verification means 19 comprise a processing stage 21 , known as a PID selector, and a key stage 22. A reproduced encrypted information signal I can be applied from the information signal input 20 to the processing stage 21. A reproduced encrypted information signal I in accordance with the ISO/IEC 13818-1 standard is formed by successive information signal blocks of 188 bytes each. These information signal blocks can accommodate a plurality of video channels and audio channels as well as additional information for a video channel or an audio channel. A reproduced encrypted information signal I contains enable information E, which forms additional information. Enable information E identifies an playing authorization allocation device of the playing authorization allocation means 5, which is enabled or authorized to allocate a playing authorization for the paid-service information signal I which contains the enable information E. The processing stage 21 has a control input 23 via which channel-control information K from input means 26 can be applied to the processing stage 21 , which input means include an up button 24 and a down button 25. By actuating the up button 24 or the down button 25 a video channel and its associated audio channel contained in the reproduced encrypted information signal I can be selected. The selected video channel, the associated audio channel as well as additional information associated with these two channels can be applied in the form of information signal blocks from the processing stage 21 to an information signal output 27 of the processing stage 21. Enable information E associtaed with the selected video channel and the accompanying audio channel can be applied to an enable output 28 of the processing stage 21. When a reproduced information signal I is a paid-service information signal I and is therefore encrypted, the reproduced information signal I is encrypted by scrambling - i.e. by time-shifting of the information signal blocks. A reproduced encrypted information signal includes a further additional information second key information S2, also known as ECM information in the DVB standard. Second key information S2 contains information about how to restore the scrambled - i.e. time-shifted - information signal blocks to the correct sequence and thus on how to decrypt them. However, such second key information S2 is also encrypted and can only form composite key information S suitable for decrypting a reproduced encrypted I in conjunction with first key information SI , which is known as EMM information in the DVB standard and which serves for decrypting the second key information S2. In order to achieve an effective protection against an unauthorized reproduction of a paid-service information signal I by non-authorized persons, the second key information S2 is changed at short periodic time intervals. The first key information SI is usually changed at long periodic intervals and is transmitted as additional information in an information signal I. A membership card 29 can be inserted into the key stage 22, which card is formed by a so-called smart card and in which first key information SI can be stored upon payment of a membership fee. When, upon payment of a fee by the owner of the membership card 29, the membership card 29 allows the owner of the membership card 29 to decrypt and thus use the paid-service information signal I during the next weeks new first key information SI is stored in the membership card 29. From the processing stage 21 second key information S2 can be applied to the key stage 22. In conjunction with the membership card 29 the key stage 22 is capable of decrypting the second key information S2 by means of first key information SI stored in the membership card 29 and last applied to a first key input 30 or to a second input 31. In the case of playing authorization the membership card 29 stores suitable first key information S 1 for the second key information S2 contained in the reproduced encrypted information signal I, as a result of which the key stage 22 is capable of jointly processing the first key information SI and the second key information S2 and supplying composite key information S suitable for correctly decrypting the reproduced encrypted information signal I. As a result, reproduced encrypted information signals I can be applied to the information signal input 20 of the verification means 19 and in the case of a playing authorization the verification means 19 can supply composite key information S for the correct decryption of the reproduced encrypted information signal I. Owing to the provision of composite key information S - formed by the first key information SI , stored in the membership card 29, and by the second key information S2, contained in the reproduced encrypted information signal I - a particularly high protection against manipulation by an unauthorized person is achieved with the arrangement in accordance with the invention. The composite key information S can be applied to decrypting means 32, which in the present case are formed by a so-called descrambler. Furthermore, a reproduced encrypted information signal I, which appears on the output 27 of the processing stage 21, can be aplied to the decrypting means 32. Decryption of the information signal I, which has been encrypted by scrambling of information signal blocks, is effected by restoring the correct time sequence - i.e. by descrambling - of the information signal blocks of the encrypted information signal I. If the reproduced information signal I is a toll-free and, consequently, non-encrypted information signal I the information signal I applied to the decryption means 32 can be transferred directly to an output 33 of the decryption means 32. However, if a reproduced information signal I available on the information signal output 27 of the processing stage 21 is a paid-service information signal I, which is consequently encrypted, the decryption means 32 effect a decryption of the encrypted information signal I. It is to be noted that the decryption means 32 - which only receives composite key information S suitable for the correct decryption of the encrypted information signal I in the case of a playing authorization - only produce a decrypted information signal I on the output 33 in the case that a playing authorization is available. However, if no playing authorization is available and the decryption means 32 do not receive composite key information S suitable for the correct decryption of the encrypted information signal I, no decrypted information signal I but merely an incorrectly decrypted and therefore, in fact, still encrypted information signal I is available on the output 33 of the decryption means 32. An information signal I avialable on the output 33 of the decryption means 32 can be applied to a demultiplexer stage 34 provided in the processing means 35, which in the present case also form part of the interrogation means for independently requesting a playing authorization. The demultiplexer stage 34 is adapted to supply the video information signal blocks corresponding to the selected video channel and contained in the information signal I to first decoder means 36 and to supply audio information signal blocks corresponding to the selected audio channel and contained in the information signal I to second decoder means 37. The first decoder means 36 are formed by an MPEG decoder and are adapted to decode the video information signal blocks encoded in accordance with an MPEG standard. A decoded digital video information signal can be applied from the first decoder means 36 to a digital-to-analog converter 38, which can supply an analog video information signal to a video output 39 of the arrangement 1. The first decoder means 36 have a control information output 40 on which control information SI is available if the first decoder means 36 do not succeed in decoding the video information signal blocks. This is the case if owing to the absence of a playing authorization not a decrypted but an incorrectly decrypted and, consequently, encrypted information signal appears and, as a result of this, incorrectly decrypted, i.e. in fact encrypted, video information signal blocks are applied to the first decoder means 36. The second decoder means 37 include an MPEG decoder and an AC-3 decoder and are adapted to decode the audio information signal blocks which have been encoded in accordance with an MPEG standard or the AC-3 standard. A decoded digital audio information signal can be suppplied from the second decoder means 37 to a digital-to- analog converter stage 41, which can supply an analog audio information signal to an audio output 42 of the arrangement 1. The TV set 4 can be connected to the video output 39 and the audio output 42 and is adapted to reproduce an information signal I. The arrangement 1 in accordance with the invention now comprises interrogation means for independently requesting a playing authorization. These interrogation means include communication means 43, which in the absence of a playing authorization for a reproduced encrypted information signal, which is characterized by the appearance of control information SI, are capable of establishing a data link to at least a playing authorization allocation device of the playing authorization allocation means 5. For this purpose, control information SI available on the control information output 40 of the first decoder means 36 can be applied to a control unit 44 of the communication means 43. Furthermore, enable information E available on the enable output 28 of the processing stage 21 can be applied to the control unit 44. The communication means 43 further comprise memory means 45 connected to the control unit 44 and adapted to store connection set-up information of playing authorization allocation devices 5 of the playing authorization allocation means, which devices are characterized by enable information E. Connection set- up information can be formed by a telephone number of a playing authorization allocation device, a given address in a radio communication network or by a given reverse channel of a cable system, as will be described in more detail hereinafter. For the communication with a playing authorization allocation device of the playing authorization allocation means 5 the comunication means 43 comprise a first communication stage 46, a second communication stage 47 and a third communication stage 48. In the present case, the first communication stage 46 is formed by a so-called modem, which is adapted to establish a data link formed by a telephone connection 49. To set up a telephone link 49 the first communication stage 46 has an input 50 arranged to receive connection set-up information in the form of a telephone number of a charge collection device which at the same time constitutes a first playing authorization allocation device 51 of the playing authorization allocation means 5. Moreover, connection set-up information in the form of a further telephone number can be applied to the input 50 of the first communication stage 46, by means of which a further telephone link 52 can be set up between the first communication stage 4 and a first broadcasting station which at the same time constitutes a second playing authorization allocation device 53 of the playing authorization allocation means 5. The first broadcasting station is adapted to transmit TV programs in the form of encrypted or non-encrypted information signals I by satellite via a satellite link 54. Furthermore, the first broadcasting station is allowed or authorized to issue playing authorizations for pay television programs transmitted by the first broadcasting station, which programs are recorded in a recording and reproducing device and can be reproduced at a later instant. Connection set-up information in the form of an address in a radio communication network can be applied to an inpuy 54 of the second communication stage 47. Using the address in a radio communication network, the second communication stage 47 is adapted to set up a data link in the form of an microwave link 56 between the second communication stage 47 and a second broadcasting station which at the same time forms a third playing authorization allocation device 57 of the playing authorization allocation means 5. For this purpose, the second communication stage 47 can supply microwave signals to a microwave antenna 58. Such microwave links between a broadcasting station and a set-top box are known as "wireless cable" radio links. The second broadcasting station 57 is adapted to transmit TV programs comnsisting of encrypted or non-encrypted information signals I via the microwave link 56 and is allowed and authorized to allocate playing authorizations for TV programs which are transmitted by the second broadcasting station, which are recorded in a recording and reproducing device and which are reproducible at a later instant. The third communication stage 48 is adapted to set up a data link to a cable TV service unit 60 via a cable TV system 59, which cable TV service unit also forms a broadcasting station and a fourth playing authorization allocation device 60 of the playing authorization allocation means 5. For this purpose, an input 61 of the third communication stage 48 is arranged to receive channel information which characterizes the reverse channel for the transmission of information to the cable TV service unit. The cable TV service unitis adapted to transmit TV programs consisting of encrypted or non-encrypted information signals I via the cable TV system 59 and is allowed and authorized to allocate playing authorizations for pay TV programs which are transmitted by the cable TV service unit, which are recorded in a recording and reproducing device and which are reproducible at a later instant. All the connection set-up information - the first and the second telephone number, the address in a radio communication network and the channel information - is stored in the memory means 45 in such a manner that when enable information E characterizing one of the playing authorization allocation devices 51, 53, 57 and 60 of the playing authorization allocation means 5 appears the control unit 44 causes the relevant connection set-up information to be read from the memory means 45. The connection set-up information thus read enables a data link to be set up from the communication means 43, i.e. the arrangement 1, to the playing authorization allocation device 51, 53, 57 or 60 identified by the enable information E. The control unit 44 is adapted to supply connection set-up information read from the memory means 45 to the input 50 of the first communication stage 46, or to the input 55 of the second communication stage 47, or to the input 61 of the third communication stage 48 in dependence upon the type of connection set-up information that has been read. Connection set-up information in the form of telephone numbers is then supplied to the first communication stage 46, connection set-up information in the form of addresses in a radio communication network is supplied to the second communication stage 47, and connection set-up information in the form of channel information is supplied to the third communication stage 48. When an encrypted paid-service information signal I is to be played from a purchased prerecorded DVHS cassette by means of the DVHS video recorder 2 and the first key information SI required for the decryption of the second key information S2 contained in the paid-service information signal I is not stored in the membership card of the key stage 22 no playing authorization exists. When a purchased or a freely distributed prerecorded DVHS has been manufactured by a firm which has transferred the collection of charges for playing of the encrypted paid-service information signal I recorded on the prerecorded DVHS cassette to the charge collection device which is formed by the first playing authorization allocation device 51, the information signal recorded on this DVHS contains enable information which identifies this first playing authorization allocation device 51. By actuating the play button 7 the DVHS video recorder 2 can be set to the play mode to reproduce the encrypted paid-service information signal from the DVHS cassette in the DVHS video recorder. The reproduced encrypted information signal I can be applied to the information signal input 20 and eventually to the processing stage 21 of the verification means 19 via the first interface means 11, the bus connection 12 and the second interfave means 13. The enable information E contained in the reproduced encrypted information signal I is detected by the processing stage 21 and is applied to the enable output 28. In a manner not shown in Figure 1 the user of the arrangement 1 may be prompted to insert a membership card 29 made available by the first playing authorization allocation device 51. If the membership card 29 does not contain the correct first key information S 1 and there is consequently no playing authorization for the encrypted information signal I reproduced from the prerecorded DVHS cassette, the decryption means 32 cannot produce a decrypted information signal I on the output 33. As a consequence, the video information signal blocks in the reproduced encrypted information signal I cannot be decoded correctly, as a result of which the first decoder means 36 supply control information SI to the control unit 44. The enable information E detected by the processing stage 21 and available on the enable output 28 of this stage is also applied to the control unit 44. The control unit 44 then reads the first telephone number from the memory means 45 in order to set up the telephone link 49 to the first playing authorization allocation device 51 identified by the enable information E and transfers this first telephone number to the first communication stage 46. The first communication stage 46 forms by a modem dials the first telephone number of the first playing authorization allocation device 51 and thus sets up the telephone link 49. After a successful set-up of the telephone link 49 the control unit 44 can supply playing authorization request information to the first playing authorization allocation device 51 via the first communication stage 46 and via the first telephone link 49. With the aid of the playing authorization request information the first playing authorization allocation device 51 , which is formed by the charge collection device, checks whether it is possible to collect the charges via an existing membership of the owner of the membership card 29 with the first playing authorization allocation device 51. On the basis of the playing authorization request information, which includes for example the date of recording of the information signal I to be reproduced, the first playing authorization allocation device 51 can determine first key information S I , which first key information SI is necessary, in conjunction with the second key information S2 contained in the paid-service information signal I, to form composite key information S suitable for the correct decryption of the reproduced encrypted paid-service information signal I. If a possibility of collecting charges from the owner of the membership card 29 exists in the first playing authorization allocation device 51 and if the appropriate first key information SI has been detected, the first playing authorization allocation device 51 can give a playing authorization by transferring the first key information S 1 to the control unit 44 of the communication stage 43 via the first telephone link 49 and the first communication stage 46. When first key information SI is available in the control unit 44 the control unit 44 can apply the first key information SI to the first key input 30 of the key stage 22. When first key information SI appears in the key stage 22 the key stage 22 is enabled to overwrite first key information S 1 previously stored in the membership card 29 with the key information S 1 received at the key input 30. The key stage 22 is adapted to supply composite key information S, which is suitable for correctly decrypting the reproduced encrypted paid-service information signal I, to the decryption means 32. As a result, the decryption means can decrypt the reproduced encrypted information signal I with the aid of the composite key information S and the processing means 35 can proces the reproduced information signal I into a video information signal available at the video output 39 and an audio information signal available at the audio output 42. Thus, the arrangement 1 in accordance with the invention is suitable for independently requesting a playing authorization. When first key information SI , which represents a playing authorization, is received the arrangement 1 is enabled to decrypt a reproduced information signal I. Manipulation by non-authorized persons is ruled out almost completely because characteristic billing information, which specifies the number of playing events of paid-service information signals, is generated in the first playing authorization allocation device device 51 upon reception of playing authorization request information and can therefore not be altered illegally by a user of the arrangement 1. Furthermore, charging of the fees to the user of the arrangement 1 in accordance with the invention can be effected at comparatively short time intervals and with a particularly low expenditure by means of the first playing authorization allocation device device 51 , i.e. the playing authorization allocation device. The first playing authorization allocation device 51 can then handle the collection of charges for a multitude of prerecorded DVHS cassettes and other digital recording media. This advantage of the common collection of charges is attainable particularly in that the enable information E contained in each paid-service information signal I identifies a respective playing authorization allocation device which is allowed and authorized to allocate a playing authorization. Moreover, it is very advantageous that setting-up the data link, supplying the playing authorization request information and obtaining the playing authorization up to the correct decryption of the reproduced encrypted paid-service information signal I can be effected within a very short time interval, as a result of which the user of the arrangement 1 in accordance with the invention has to wait only very briefly for the reproduction of the paid-service information signal. A further advantage of the charge collection is that a manufacturer of prerecorded data carriers - such as DVHS casettes, DVDs or CD-ROMs - can give a prerecorded data carrier to customers and can receive earnings through the charge collection each time that the prerecorded record carrier is played. In a second example of an application an encrypted paid-service information signal I can be reproduced from a DVD 16 by means of the DVD apparatus 3. The enable information E contained in the reproduced encrypted information signal I identifies the first broadcasting station as a second playing authorization allocation device 53 authorized to allocate a playing authorization. In the absence of a playing authorization, which - as already explained hereinbeffore - is characterized by the occurrence of control information SI, the communication means are capable of setting up a data link, which is formed by the telephone link 52, to the first broadcasting station identified by the enable information E. The communication means 43 are further adapted to supply playing authorization request information to the first broadcasting station via the telephone link 52 and to receive a playing authorization for the reproduced encrypted information signal I from the first broadcasting station via the telephone link 52. After the first key information SI which represents the playing authorization has been received and after the first key information SI has been stored in the membership card 29 the encrypted paid-service information signal I can be decrypted correctly in the decryption means 32 and can be reproduced by means of the TV set 4. In a third example of an application enable information E, which is contained in a reproduced encrypted paid-service information signal I and which is reproduced from a hard-disc drive of a computer, not shown in Figure 1 , identifies the second broadcasting station as the third playing authorization allocation device device 57 for the reproduced encrypted paid-service information signal I. In the present case playing authorization request information is transferred from the control unit 44 to the second broadcasting station via the second communication stage 47 and the microwave antenna 58 by means of the microwave link 56. In the case of a playing authorization allocated by the second broadcasting station this authorization is transferred to the control unit via the microwave link 56, the microwave antenna 58 and the second communication stage 47 and is stored in the membership card 29, thus enabling a correct decryption of the reproduced encrypted information signal SI. In a further example of an application enable information E, which is contained in an encrypted paid-service information signal I reproduced from a DVD by means of a DVD apparatus 3, identifies the cable TV service unit, i.e. the fourth playing authorization allocation device 60. In the present case playing authorization request information, which identifies paid-service information signal to be reproduces, is transmitted to the cable TV service via the cable TV system 59 over the reverse channel identified by the channel information. The cable TV service unit can transmit first key information SI representing a playing authorization to the communication means 43 over the same channel or another channel of the cable TV system 59. Thus, the communication means 43 of the arrangement 1 in accordance with the invention are adapted to supply playing authorization request information which identifies the reproduced encrypted information signal I and to receive first key information SI, which depends on the playing authorization request information, from at least one playing authorization allocation device. This yields the advantage that on the basis of the playing authorization request information each playing authorization allocation device can detect which paid-service information signal I is to be reproduced by the user of the arrangement 1. Thus, it is possible, for example, to charge a higher fee for a particularly popular movie recorded on a prerecorded DVHS video cassette than for a less popular movie. Moreover, the amount to be charged can depend on whether a movie to be played has already been played several times by the owner of the membership card and a quantity discount can be granted. The arrangement 1 further includes control means 62 to which the control information SI from the control information output 40 of the first decoder means can be applied in the absence of a playing authorization. The control means 62 can further receive playing authorization information WB from the control unit 44, which information is supplied by the control unit 44 when first key information S 1 supplied by a playing authorization allocation device is available. In the absence of a playing authorization for a paid-service information signal I reproduced by the DVHS video recorder 2, which absence is characterized by the occurrence of control information SI, the control means 62 are adapted to supply pause information to the DVHS video recorder 2 via the second interface means 13, the bus connection 12 and the first interface means 11 in order to interrupt the reproduction of the paid-service information signal. Moreover, if subsequently a playing authorization is present for the paid-service information signal I reproduced by the DVHS video recorder 2, which presence is characterized by the occurrence of playing authorization information WB, the control means 62 are adapted to supply end-of-pause information to the DVHS video recorder 2 via the second interface means 13, the bus connection 12 and the first interface means 11 and to set the DVHS video recorder 2 to the play mode. Similar pause information and end-of-pause information can be applied to any reproducing device - i.e. also to the DVD apparatus 3 - which is connected to the second interface means 13 via the bus connection 12 and which reproduces an encrypted information signal I. This yields the advantage that the reproduction of a paid-service information signal I is interupted until a playing authorization from a playing authorization allocation device device is available and the user of the arrangement 1 consequnetly does not miss any part of the paid-service information signal I when this is reproduced. The arrangement 1 further includes receiving means 63 for receiving an encrypted or non-encrypted information signal I from a plurality of broadcasting stations. For this purpose, a tuner stage 64 of the receiving means 63 is adapted to receive information signals I from the cable TV service unit, i.e. the fourth playing authorization allocation device 60, via the cable TV system 59 and from the second broadcasting station, i.e. the third playing authorization allocation device 57, via the microwave link 56 and the microwave antenna 58. Furthermore, the tuner stage 64 is adapted to receive information signals I from a third broadcasting station 65 via a terrestrial radio link 66 and a terrestrial antenna 68 provided in an antenna stage 67. In addition, the tuner stage 64 can receive information signals I from the first broadcasting station 53 via the satellite radio link 54 and a satellite antenna 69 of the antenna stage 67. Channel control information K, which can be generated by the entry means 26 through actuation of the up button 24 or the down button 25 , can be applied to the tuner stage 64 and to the control input 23 of the procesing stage 21. Depending on the channel control information K an information signal I received in the tuner stage 64 is applied to the information signal input 20 of the verification means 19. An information signal I applied to the information signal input 20 can be supplied to the processing stage 21. In the processing stage 21 - as already explained hereinbefore - the information signal blocks of the video channel and the associated audio channel selected by means of the up button 24 and the down button 25 as well as the additional information associated with the information in these two channels - particularly the corresponding enable information E and the second key information S2 - are selected on the basis of the channel control information K. The selected information can be made available on the information signal output 27. A information signal I available on the information signal output 27 - which signal can be a paid-service information signal I, which is consequently encrypted and which then contains enable information E which identifies a playing authorization allocation device allowed to allocate a playing authorization for the encrypted information signal I - can be supplied to the second interface means 13 of the arrangement 1. It is to be noted that it is also possible to select a plurality of video channels, audio channels as well as additional information associated with the information in these two channels and to record all this information by means of the DVHS video recorder 2. First key information SI contained in the information signal received from a broadcasting station can be detected in the processing stage 21 and can be applied to the second key input 31 of the key stage 22 in order to store the first key information S 1 in the membership card 29. By actuating the record button 8 of the entry means 6 of the DVHS video recorder 2, which constitutes a recording and reproducing device, the DVHS video recorder 2 can be set to a recording mode. When the recording mode is active the DVHS video recorder 2 can record information signals I, which are applied from the second interface means 13 to the first interface means 11 via the bus connection 12, on the magnetic tape 9 of a DVHS cassette via the operating connection 10. An encrypted paid-service information signal I recorded by means of the DVHS video recorder 2 can be played back in a reproducing mode activated by actuation of the play button 7, as already set forth hereinbefore. This yields the advantage that also for a movie transmitted by a broadcasting station and recorded on a DVHS cassette by the DVHS video recorder 2 the broadcasting station can be charge a fee for each reproduction of the pay movie. In this respect, it is to be noted that a playing authorization for a paid- service information signal I supplied by the third broadcasting station 65 can be granted by the charge collection device, i.e. the first playing authorization allocation device 51 , which is allowed by the third broadcasting station 65 to allocate playing authorizations. It is to be noted that all the playing authorization allocation devices include memory means capable of storing information about all the paid-service information signals I for which the respective playing authorization allocation device is allowed and authorized to allocate a playing authorization. This information includes in particular identification information, which is likewise contained in playing authorization request information and which identifies the information signal I to be reproduced. Moreover, for the identification information identifying each paid-service information signal it is possible to store associated first key information S 1 for decrypting the encrypted information signal as well as billing information which indicates the amount to be charged for the relevant paid- service information signal. It is to be noted that the memory means 45 may already contain connection set-up information when an arrangement 1 in accordance with the invention is purchased. Moreover, connection set-up information for a new playing authorization allocation device can be stored on an associated membership card 29, which information can be supplied to the control unit 44 via a connection not shown in Figure 1 in order store the connection set-up information in the memory means 55 when the membership card 29 is inserted into the key stage 22. Furthermore, a new playing authorization allocation device can supply the corresponding connection set-up information to the arrangement 1 via a data link in order to store the connection set-up information in the memory means 45. It is to be noted that the communication means can also be adapted to set up a data link to an internet network server which constitutes a playing authorization allocation device. Furthermore, it is to be noted that an arrangement in accordance with the invention can also be built directly into a video recorder, or in a DVD apparatus, or in a TV receiver. In the embodiment described hereinbefore by way of example the interrogation means for independently requesting a playing authorization for a reproduced encrypted information signal basically comprise the communication means 43 and the processing means 35, of which the first decoder means 36 at the same time serve as detection means for detecting an encrypted and a non-encrypted or decrypted information signal. Such a construction of the interrogation means has proved to be particularly advantageous in practice. However, it is to be noted that alternatively an arrangement in accordance with the invention may comprise differently constructed interrogation means. Such interrogation means can be, for example, means in which the first decoder means for decoding encoded video information signal blocks are not used at the same time as detector means for detecting encrypted or non-encrypted information signals but in which separate detector means are provided by which encrypted or non-encrypted information signals can be detected. It is likewise possible to provide interrogation means with communication means having another circuit design than in the arrangement in accordance with the invention described with reference to Figure 1.

Claims: CLAIMS: 1. An arrangement (1) for verifying a playing authorization for a reproduced encrypted information signal - which is reproduced by means of a reproducing device (2, 3) adapted to cooperate with the arrangement (1) - and for supplying a decrypted information signal when a playing authorization is available, comprising verification means (19) arranged to receive a reproduced encrypted information signal and adapted to supply key information (S) suitable for correctly decrypting the reproduced encrypted information signal when a playing authorization is available, and decryption means (32) arranged to receive key information (S) and adapted to decrypt the reproduced encrypted information signal when suitable key information (S) is available, characterized in that the arrangement (1) is equipped with interrogation means (35, 43) for independently requesting a playing authorization. 2. An arrangement (1) as claimed in Claim 1, characterized in that the interrogation means (35, 43) include communication means (43) which are adapted to set up a data link (49, 52, 56, 59) between the communication means (43) and at least one playing authorization allocation device (51, 53, 57, 60) in the absence of a playing authorization for a reproduced encrypted information signal, and the communication means (43) are adapted to supply playing authorization request information to the playing authorization allocation device (51 , 53, 57, 60) via the data link (49, 52, 56, 59) and to receive a playing authorization for the reproduced encrypted information signal from the playing authorization allocation device (51, 53, 57, 60). (Fig. 1) 3. An arrangement (1) as claimed in Claim 2, characterized in that the verification means (19) are adaapted to read out and supply enable information which is contained in a reproduced encrypted information signal and which identifies a playing authorization allocation device allowed to allocate a playing authorization for the reproduced encrypted information signal, and the communication means (43) are adapted to supply playing authorization request information to the playing authorization allocation device (51, 53, 57, 60) identified by the enable information. (Fig. 1) 4. An arrangement (1) as claimed in Claim 3, characterized in that receiving means (63) have been provided for receiving an encrypted information signal supplied by a broadcasting station (53, 57, 60, 65), the encrypted information signal containing enable information which identifies a playing authorization allocation device (51 , 53, 57, 60) allowed to allocate a playing authorization for the encrypted information signal, and interface means (13) have been provided for supplying an encrypted information signal containing the enable information to a recording and reproducing device (2) adapted to cooperate with the interface means (13) in order to record the encrypted information signal. (Fig. 1) 5. An arrangement (1) as claimed in Claim 3, characterized in that the communication means (43) comprise memory means (45) in which connection set-up information from playing authorization allocation device (51, 53, 57, 60) identified by enable information can be stored, and the communication means (43), in the absence of a playing authorization for a reproduced encrypted information signal containing given enable information, are adapted to set up a data link (49, 52, 56, 59) by means of the connection set-up information stored in the memory means (45) for supplying playing authorization request information to the playing authorization allocation device (51, 53, 57, 60) identified by the given enable information, and to receive a playing authorization for the reproduced encrypted information signal via the data link (49, 52, 56, 59). (Fig. 1) 6. An arrangement (1) as claimed in Claim 2, characterized in that the communication means (43) are adapted to supply playing authorization request information identifying the reproduced encrypted information signal to a playing authorization allocation device (51, 53, 57, 60) and to receive key information (SI) from the playing authorization allocation device (51, 53, 57, 60), which key information is dependent on the playing authorization request information. 7. An arrangement (1) as claimed in Claim 2, characterized in that processing means (35) have been provided for decoding a reproduced non-encrypted information signal, which means also form part of the interrogation means (35, 43), and the processing means (35) are adapted to supply control information (SI) to the communication means (43), which control information is characteristic of an incorrect decryption of a reproduced encrypted information signal owing to the absence of a playing authorization. (Fig. 1) 8. An arrangement (1) as claimed in Claim 2, characterized in that the verification means (19) include a key stage (22) which is arranged to receive first key information (SI) received in the communication means (43) from a playing authorization allocation device (51, 53, 57, 60) and to receive second key information (S2) contained in the reproduced encrypted information signal, and the key stage (22), when a playing authorization is available, is adapted to jointly process the first key information (SI) and the second key information (S2) and to supply composite key information (S) to the decryption means (32), which composite key information is suitable for the correct decryption of the reproduced encrypted information signal. (Fig. 1) 9. An arrangement (1) as claimed in Claim 1, characterized in that control means (62) have been provided which are adapted to supply, in the absence of a playing authorization, pause information to the reproducing device (2, 3) via interface means (13) in order to interrupt the reproduction of an encrypted information signal, and the control means (62) are adapted to supply, when subsequently a playing authorization for the encrypted information signal is available, end-of-pause information to the reproducing device (2, 3) via the interface means (13) in order to continue reproduction of the encrypted information signal. (Fig. 1).

Inventors: PROIDL ADOLF, PROIDL, ADOLF
Applicants: KONINKL PHILIPS ELECTRONICS NV, PHILIPS SVENSKA AB, KONINKLIJKE PHILIPS ELECTRONICS N.V., PHILIPS AB
Application year: 1998
Main classification: H04N7
IPC codes: H04N7