JP3512878B2 - Packet signal scramble or descramble method, and scramble or descramble device - Google Patents

Description

Detailed Description of the Invention

[0001]

[Industrial field] In recent digital broadcasting, IS
As represented by the concept of DB (Integrated Digital Broadcasting), various program elements such as video, audio, still images, character data, note data, and computer programs are handled in a unified digital signal format. A packet transmission method is used as a technical method for this purpose.

Although these program elements may constitute a program independently, a plurality of types of program elements are combined to form a program.
Sometimes one program is composed, which is a so-called multimedia program.

Further, it is general that several programs are simultaneously broadcast on one broadcast wave. This is what is called multi-channel broadcasting. Like this
In the environment of multimedia programs and multi-channel broadcasting, the demand for pay broadcasting will be more diverse than conventional broadcasting. In addition to contracts and charges for each program of multi-channel broadcasting, partial contracts and charges for multimedia programs are also required.

The present invention relates to a technique for utilizing a scramble system for realizing pay broadcasting in digital broadcasting by a packet transmission system, and particularly easily realizes support for various contracts / billing forms of multimedia programs. The present invention relates to a method for scrambling or descrambling a packet signal for performing the same, and a scrambling or descrambling device for use in the method.

[0005]

2. Description of the Related Art As a scrambling technique in digital broadcasting by a packet transmission system, a data channel scrambling system in satellite television broadcasting and high definition television broadcasting in Japan, and M in Europe.
Various methods such as a voice / data scramble method in the AC-Packet method have been developed.

[0006]

However, each of these systems is intended for a single or at most two program elements such as television broadcasting and independent data broadcasting, and is a full-fledged multimedia program. It did not take into account the simultaneous broadcasting of many program elements in.

That is, when a plurality of program contents in a multimedia program are scrambled by using such a scrabble method, generally, a scrambler for each program element (the receiver side also similarly descrambles for each program element). (Scrambler) (In the following, the scramble on the transmitting side and the descramble on the receiving side are collectively expressed as scramble / descramble)
Was needed. Moreover, with this method, the significance of integrating the program elements in digital broadcasting cannot be utilized, the circuit scale becomes large because a plurality of scramble / descramble circuits are required, and the number of program elements required for the foreseeable future remains unchanged. It is not realistic because there are many problems such as lack of guarantee that the required number of program elements is sufficient, and lack of expandability.

As a scrambling method for a plurality of program elements in a multimedia program, one scrambling /
Obviously, it is desirable that the descrambling device can be shared in terms of circuit scale and expandability.

Further, although the purpose is different from the present invention,
Among the packet transmission scramble methods, there is a method used as a scramble key update method.
The scramble key update method in two cases will be described below.

(1) Key renewal timing signal system The renewal timing signal is provided in the header portion of the packet, as well as having two scramble key storage areas for the current key and the next key. First, the new scramble key is temporarily stored in the storage area of the next key by the key distribution means. Furthermore, the key update timing signal is transferred to the current key storage area at the time of the activated packet, and is actually used for scrambling from this packet.

(2) A / B key system Two key storage areas, an A key and a B key, are provided, and an A / B key instruction signal is arranged in the header portion of the packet.
It is now assumed that the A / B instruction signal indicates the use of the A key and the A key is actually used for scrambling. First, a new scramble key, that is, a B key is stored in the B key storage area by the key distribution means. Further, since the A / B key indication signal indicates the B key, the new scramble key, that is, the B key is actually used for scrambling.

In the conventional scrambling method using these conventional scrambling key updating methods, when a multimedia program is scrambled / descrambled by a common scramble / descrambler, one common program is used for all program elements. You need to use the scramble key. The reason is that in the conventional scramble method,
In each of the above (1) and (2) scramble key updating methods, two scramble key storage areas are provided, and one of them is used as a temporary storage area for scramble key update, so that it can be actually used for scrambling. This is because there is only one key.

Under this circumstance, when trying to set a partial reception contract for a combination of some program elements of a multimedia program, it is not possible to distinguish the contract form by distinguishing the scramble key. The only way to realize it is to use a method other than the scramble key, such as a method of selecting elements by packet identifier. However, in the scrambling method using these key update methods, the same scramble key as that of all subscribers has been distributed to the partial subscribers, so the partial subscriber invalidates the sorting circuit based on the packet identifier. It is possible to easily receive all the program elements by performing fraud such as doing.

In order to solve the above-mentioned various problems, an object of the present invention is to (1) enable scramble / descramble of a plurality of program elements of a multimedia program with a single scramble / descramble device, (2) Moreover, it is possible to set various contract forms such as not only a reception contract for all program elements of the multimedia program but also a partial reception contract for a combination of some program elements,
Furthermore, (3) In that case, a scramble or descramble method of digital broadcasting by a packet transmission method that makes it difficult for a partial reception contractor to illegally descramble all program elements, and a scramble or descramble apparatus for that purpose. It is the one we are trying to provide.

[0015]

In order to achieve the above object, the scrambling or descrambling method of the present invention comprises:
In a method of scrambling or descrambling a packet signal for digital broadcasting, in which signals of a plurality of program elements constituting a program are time-division multiplexed in a packet format and transmitted, the plurality of program elements are M types (M is 2 or more). (Integral number) program element groups and different reception qualifications are set for the M kinds of program element groups, the scrambling is performed while sequentially changing the allocation of the scramble key candidates used in the method. When updating the key candidates and scrambling or descrambling the program element group,
The total number of the scramble key candidates is N (N is an integer of 3 or more), and regarding the allocation of the scramble key candidates, one scramble key candidate is distributed among the N scramble key candidates. And assigning the remaining N-1 scramble key candidates to the M-type program element groups, one for each of the M-type program element groups. is there.

Further, the scrambling or descrambling method of the present invention relates to allocation of the scramble key candidates, in addition to the method according to claim 1, for any two kinds of combinations in the M kinds of program element groups, It is characterized in that scramble key candidates different from each other are assigned at least during a certain period.

In the scrambling or descrambling method of the present invention, the M kinds of program element groups are composed of one kind of basic program element group and M-1 kinds of special program element group. Regarding the allocation of the scramble key candidates, in addition to the method according to claim 1 or 2, one scramble of the remaining N-1 scramble key candidates is added to the one type of basic program element group. Key candidates are allotted, and N-2 scramble key candidates that are still remaining are sequentially assigned to the N-2 types that are sequentially selected from the M-1 special program element group, and the remaining (( M-
1)-(N-2)) If there are special program element groups, the scramble key candidates assigned to the basic program element group are redundantly assigned to the special program element group. It is characterized by.

The scrambling or descrambling apparatus of the present invention further comprises scrambling key storage means having N (N is an integer of 3 or more) scrambling key candidate storage area.
According to the scramble key distribution means for distributing the scramble key candidates to the respective key candidate storage areas of the scramble key storage means and the scramble key selection information arranged in the header part of the unprocessed packet signal, N pieces of the scramble key storage means are provided. Of the scramble key stored in the key candidate storage area, and selects one scramble key from the scramble key candidates read from the area, and the scramble key is selected according to the scramble key selected by the key select means. It is characterized by comprising scrambling or descrambling means for scrambling or descrambling the data portion of the unprocessed packet signal in which the key selection information for selection is arranged.

Further, in the scramble or descramble apparatus of the present invention, the scramble or descramble means may start scrambling or descrambling each packet of the unprocessed packet signal,
It is characterized in that it is configured to be initialized only by the selected scramble key and the information of the header part and the data part of the packet.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a basic configuration of a scramble / descramble apparatus according to the present invention. First, the key candidates 11, 12, 13, ... Distributed by the scramble key distribution unit 1 are stored in the scramble key storage unit 2. Here, the scramble key storage means 2 is provided with storage areas 21, 22, 23, ... That store three or more N key candidates independently. The scramble key distribution means 1 distributes a scramble key independently to each of these key candidate storage areas.

On the other hand, the unprocessed packet signal 5 is input to the scramble key selection means 3 and the scramble / descramble means 4, is subjected to scramble / descramble processing described below, and is output as a processed packet signal 6.

In the scramble key selection means 3, the key candidate storage area 2 of the scramble key storage means 2 is in accordance with the scramble key selection information in the header portion of the unprocessed packet signal 5.
Key candidates 31, read from 1, 22, 23, ...
One of the scramble keys 7 out of 32, 33, ...
Select and scramble / descramble means 4
Supply to.

In the scramble / descramble means 4, based on the scramble key 7, the unprocessed packet signal 5
The data portion of is scrambled / descrambled and output as a packet signal 6 after processing.

FIG. 2 is a diagram for explaining the basic operation of the packet signal scrambling / descramble method according to the present invention. That is, it is a diagram for explaining a method of scrambling / descrambles M types of program element groups for which different reception qualifications are set by using the scramble / descramble apparatus shown in FIG.

In FIG. 2, the unprocessed packet signal 5 input to the scramble / descramble apparatus after the time A prior to the distribution of the scramble key has the first scramble key selection information arranged in the header portion. It is restricted to select the scramble key candidate 31 of. Next, at time B, the scramble key distribution means 1 distributes the key candidate 11 to the scramble key storage means 2,
This is stored in the first key candidate storage area 21. Finally,
At time C after the scramble key distribution is completed,
The restriction on the selection of the first key candidate 31 imposed on the scramble key selection information of the packet signal 5 is released. At this time point C, the series of scramble key distribution procedures are completed, and the next scramble key distribution procedure can be started. In the subsequent scramble key distribution procedure, key distribution is sequentially performed to different key candidate storage areas, and all scramble key candidates are distributed by a plurality of key distribution procedures.

By distributing the scramble key in this procedure, it is not necessary to manage the timing of distribution of the scramble key, which has a relatively low frequency, to the time accuracy of the packet signal, which has a high frequency. That is, time point B is time point A and time point C
It just needs to be put in between. The time period during which the scramble key distribution is possible between the time points A and C will be referred to as a scramble key distribution period here.

As shown in the above-mentioned procedure, during the scramble key distribution period, the first key candidates 11, 31 being distributed are just being distributed.
Is restricted to be selected as the scramble key. Therefore, in this period, when the total number of key candidates is N (N is an integer of 3 or more), the number of actually usable key candidates is N-1.

One of each of the N-1 key candidates is selected and assigned to the M kinds of program element groups, and scramble / descramble is performed. At this time, the value of M is N
If the value exceeds -1, it is necessary to duplicately assign the same key candidate to different program element groups.

Furthermore, when this duplicate allocation becomes necessary, pay attention to the combination of any two kinds of program element groups,
By assigning different scramble key candidates at least during a certain scramble key distribution period, it becomes possible to prevent illegal descrambling of program element groups having different reception qualifications. This is because during the scramble key distribution period in which the different scramble key candidates are assigned, the arbitrary two kinds of program element groups use independent scramble keys, so that at least fraud during this period is impossible. Because.

FIG. 3 is a diagram showing a first embodiment of a scramble / descramble method according to the present invention. Specifically, FIG. 3 shows a key candidate storage area (2 in FIG. 1).
1, 22, 23) is 3, and the number M of program element groups for which different reception qualifications are set is 2. In the figure, the three key candidate storage areas are represented by X, Y, and Z, and the key candidates distributed to the respective storage areas are represented in time order as X1, X2, X3, .... Further, the program element groups B and E represent two kinds of program element groups respectively constituting the basic service and the special service.

The respective columns (second column and third column) of the program element groups B and E show the scramble key used for scrambling / descramble and the selection period thereof. For example, during the period indicated by X1 in the basic service, the key candidate X1 is selected as the scramble key, and the packet signal belonging to the program element group is scrambled / descrambled. Note that, in FIG. 3, the program element groups B and E are displayed independently for easy understanding, but in reality, the packet signals of these program element groups are time-division multiplexed into one signal. Is being processed.

The key distribution column (uppermost column) shows the contents of scramble key distribution and the period for key distribution. For example, the display of X1 / B indicates that the key candidate X1 is distributed to the qualified recipients of the program element group B.

In this embodiment, one of the three key candidate storage areas is used for key distribution, and the remaining two are used for scramble keys of the program element groups B and E, respectively. At the end of the period for the scramble key distribution, the distributed new scramble key candidates are used as new scramble keys in the order of the program element groups B, E, B, E. At the same time, the area used for the old scramble key is sequentially used as the area for the next scramble key distribution.

In this embodiment, two types (M = 2) of program element groups are supported. Since these two types of program element groups use scramble keys that are independent of each other, their independence is ensured. Generally, when the number of key candidate storage areas is N, it is possible to scramble / descramble M = N−1 kinds of program element groups with completely independent scramble keys.

Further, according to this embodiment, the basic service contract provided only by the program element group B and the program element group B
A two-way service contract form, which is a special service contract serviced by E and E, can be implemented. In this case, the basic service contractor is entitled to receive only the program element group B, and the special service contractor is entitled to receive the program element groups B and E. Here, if the expressions representing such service contents are taken, the basic service contract and the special service contract can be paraphrased as a partial service contract and a comprehensive service contract, respectively.

The shaded portions in FIG. 3 indicate scramble keys and program element groups that are eligible for reception in the basic service contract. As described above, in the basic service contract, the receiver cannot receive the program element group E for which the scramble key distribution cannot be obtained.

FIG. 4 is a diagram showing a second embodiment of the scramble / descramble method according to the present invention. In this embodiment, the number N of key candidate storage areas is 3 and the number M of program element groups for which different reception qualifications are set is 4. Further, unless otherwise specified, the representation method of the figures and the usage method of the symbols are shown according to the first embodiment.

In the present embodiment, one of the three key candidate storage areas is used for key distribution, and the remaining two are four program element groups B and scramble keys of E1, E2 or E3. Used for delivery. At the end of the period for the scramble key distribution, the new distributed scramble key candidates are set to the program element groups B, E1, B, E2, B, E.
It is used as a new scramble key in the order of 3 ... At the same time, the storage area used for the old scramble key is sequentially used as the storage area for the next scramble key distribution. In this case, the program element group E1,
E2 and E3 receive the allocation of the scramble key of the dedicated program element group E in the period of 1/3 of the whole, but the remaining 2/3 of the period in which the exclusive scramble key is not assigned, Use a scramble key for.

Further, in this embodiment, the basic service program element group B and the three special service program element groups E1, E2,
It supports a total of four program element groups with E3. The special service program element group has at least a certain period (1 / of the whole
3)), since independent scramble keys are used, the independence of each is secured. In FIG. 4, in the case of four (M = 4) program element groups including three (N = 3) key candidates and one basic service program element group and three special service program element groups. However, in this example, if N = 3 or more, it is possible to scramble / descramble any M kinds of program element groups regardless of the value of N.

According to this embodiment, the basic service contract provided only by the program element group B, the program element groups B and E1, the program element groups B and E2, and the program element groups B and E.
There are three forms of special service contracts that can be implemented in each of the three. In this case, the basic service contractor is qualified to receive only the program element group B, and each special service contractor receives the program element groups B and E1, the program element groups B and E2, and the program element groups B and E3, respectively. Have a qualification.

Further, according to this embodiment, the basic service contract is provided only by the program element group B, the program element groups B and E1, the program element groups B, E1 and E2, the program element groups B, E1, E2 and A four-tiered hierarchical service contract form is also feasible, including three forms of special service contracts served on each of the E3s. In this case, the basic service contractor is entitled to receive only the program element group B, and each special service contractor has the program element group B and E, respectively.
1, program element groups B, E1 and E2, program element groups B, E
It is eligible to receive 1, E2 and E3.

The shaded portions in FIG. 4 indicate scramble keys and program element groups that are eligible for reception in the special service contract corresponding to the program element groups B and E1. Also, the portions shown by dots in the figure show program element groups that are originally not qualified to receive, but may be received if the illegal scramble is attempted using the obtained scramble key. In the other portions shown in white, an independent scramble key dedicated to each program element group is used, and thus unauthorized reception is impossible. Therefore, even if an illegal reception is attempted, it is impossible to completely receive a program element group that is not eligible for reception. Especially in the case of a digitally encoded signal, the loss of a part of the signal is usually fatal to the whole. Since it has an adverse effect, the security against unauthorized reception is sufficiently secured.

Next, in the scramble / descramble apparatus according to the present invention shown in FIG. 1, especially the scramble / descramble means 4 will be examined. The scramble / descramble means 4 in FIG. 1 can be generally classified into the following two types.

(1) A storage element that does not span packets. For example, it is as follows. That is, in the pseudo random number signal addition method, the type that initializes the pseudo random number signal generator for each packet. Also, in the encryption method, a type that completes processing within a packet, including the case of performing cipher chaining.

(2) A storage element that spans packets. For example, it is as follows. That is, in the pseudo random number signal addition method, the pseudo random number signal generator is not initialized for each packet but continuously operated. Also,
In cryptography, a type that performs cipher chaining over packets.

FIGS. 5 (a) and 5 (b) are block diagrams showing an example of the configuration of the scramble / descramble means of these two types. First, in the case of the type of scramble / descramble which does not have a storage element extending over packets, the scramble / descramble means 4 shown in FIG. 1 can be simply applied as it is, as shown in FIG.

Next, in the case of scramble / descramble of the type having storage elements extending over packets, as shown in FIG. 5B, a plurality of storage elements 41 controlled by the storage element switching circuit 40, 42 and 43, and these must be switched for each program element group (see FIGS. 2 and 3). This is because the descramble apparatus on the receiver side according to the present invention performs or does not perform descramble processing for each program element group according to the contract form such as a basic contract or a special contract. This is because correct scramble / descramble operation cannot be performed unless the storage elements are separated for each group.

Considering the above points, the scramble / descramble means 4 in FIG.
As described above, a device that does not have a storage element that straddles packets is more excellent in the appropriateness of the device scale or the ease of the device configuration.

When a scramble / descramble means of a type having no storage element extending between packets is used, the scramble / descramble processing can be performed regardless of the type and order of packets passing through the scramble / descramble means. Since it becomes possible, there is also an advantage that the transmission side does not need to manage the multiplexing order of the packet of each program element, and the receiving side does not have to select the packet of the program element.

6 and 7 are diagrams showing an embodiment in which the scrambling method or device according to the present invention is applied to the MPEG2 multiplexing system. FIG. 6 is a block diagram showing a concrete configuration example of the scramble apparatus, and FIG. 7 is a diagram showing the packet signal format thereof.

In this embodiment, the number N of scramble key candidate storage areas is 3. The basic and overall operation is the same as that described with reference to FIG. 1, and therefore the description thereof will be omitted. However, in the following, particularly, the added / supplemented portion will be described in the operation description of FIG. In FIG. 6, scramble key selecting means 3
Selects a key candidate based on the scramble key selection information arranged in the header part of the unprocessed packet signal. MP
In the EG2, the value 00 of the scramble control bit indicates that scrambling is not performed, and other values are to be determined for each application case. Therefore, in this embodiment, 0 is set.
Three kinds of values other than 0, 01, 10, and 11 will be used to represent selection of three types of key candidates.

The detailed operation of the scramble / descramble means 4 is as follows. That is, the scramble key 7 has the packet identifier (PID) (13) of the header portion shown in FIG.
Bit) and the continuity index (4 bits). The linear feedback shift register 52 is initialized for each successive packet with the modified scramble key as an initial value. The output of the linear feedback shift register 52 is sent to the non-linear combination circuit 53 and is non-linearly combined with the output of the shift register 56. The output of the non-linear combination circuit 53 is validated by the gate circuit 54 only during the period corresponding to the data portion of the packet shown in FIG. 7, and is added to the unprocessed packet signal 5 by the adder circuit 55 and the processed packet signal 6 That is, it is output as a scrambled packet signal. The processed packet signal 6 is also input to the shift register 56, and its output is fed back to the nonlinear coupling circuit 53.

Here, the scramble key modification circuit 51 and the non-linear combination circuit 53 are combinational logic circuits. Especially the latter is a coupling circuit containing non-linear elements. The adder circuit 55 is an adder circuit modulo 2, that is, an exclusive OR logic circuit.

Although the configuration of the scrambler (transmission side) has been described above with reference to FIGS. 6 and 7, the unprocessed packet signal is used as a scrambled packet signal and the input of the illustrated shift register 56 is processed. By changing the connection to the previous packet signal 5, the descrambling device (reception side) is configured.

[0055]

According to the present invention, (1) a single scramble / descrambler can scramble / descramble a plurality of program elements of a multimedia program,
(2) Moreover, it is possible to deal with various contract forms such as not only the reception contract for all program elements of the multimedia program but also the partial reception contract for a combination of some program elements. (3) In that case In addition, it is possible to implement a scramble / descramble method of digital broadcasting by a packet transmission system, which makes it difficult for a partial subscriber to illegally descramble all program elements, and to realize an apparatus therefor. . Furthermore, according to the present invention, (4) the scramble / descramble device according to the present invention can be configured with an appropriate circuit scale and at a low cost. (5) Multiplexing order of packets of program elements on the transmitting side It is also possible to obtain the advantage that the management of the packet and the selection of the packet of the program element on the receiving side are unnecessary.

From the viewpoint of operation of the benefits obtained by the present invention, the scramble key is updated by providing two scramble key areas, for example, and by alternately using them for the current and update areas. On the other hand, according to the present invention, by making the scramble key areas three or more, even if one area is used for updating, it is possible to always use a plurality of areas as the current one. , By operating the current scramble keys in multiple areas in various ways, such as language-based contracts in multilingual broadcasting, hierarchical contracts for basic services and special services in multimedia broadcasting, etc. (for completely independent services, Scramble / descramble of pay scramble broadcasting that has a common service part and sets multiple contract ranges It is possible to perform in a scrambled / descrambling devices.

Further, according to the present invention, by combining with a scramble / descramble circuit which is initialized for each packet and has no memory spanning between packets, the type of packet passing through the scramble / descramble circuit and Since the processing can be performed regardless of the order, one scramble / scramble is used in a service having multiple program elements such as multilingual broadcasting and multimedia broadcasting, and a service having hierarchical program elements in hierarchical encoding / transmission. When the descramble circuit is shared, the scale of the scramble / descramble device is made appropriate, and it is unnecessary to manage the multiplexing order of the packet of each program element on the transmitting side and to select the packet of the program element on the receiving side. Easy operation becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a scramble / descramble apparatus according to the present invention.

FIG. 2 is a diagram illustrating a basic operation of a scramble / descramble method according to the present invention.

FIG. 3 is a diagram showing a first embodiment of a scrambling / descramble method according to the present invention.

FIG. 4 is a diagram showing a second embodiment of a scramble / descramble method according to the present invention.

5 is a block diagram showing a configuration example of two types of scramble / descramble means in the scramble / descramble device shown in FIG. 1. FIG.

FIG. 6 is a block diagram showing a specific configuration example of the scrambler when the scrambler according to the present invention is applied to the MPEG2 multiplexing system.

FIG. 7 is a diagram showing a packet signal format applied to the scramble device shown in FIG.

[Explanation of symbols]

1 scramble key distribution means 2 scramble key storage means 3 scramble key selection means 4 scramble / descramble means 5 unprocessed packet signal 6 processed packet signal 7 scramble key 11, 12, 13 (distributed) scramble key candidates 21, 22 , 23 Key candidate storage area 31, 32, 33 (stored) scramble key candidate 40 Storage element switching circuit 41, 42, 43 Storage element 51 Scramble key modification circuit 52 Linear feedback shift register 53 Non-linear combination circuit 54 Gate circuit 55 Addition Circuit 56 Shift registers A, B, C Time points X ₁ , X ₂ , X ₃ , ... Scrambling keys Y ₁ , Y ₂ , Y ₃ , ... Scrambling keys Z ₁ , Z ₂ , Z ₃ ,. Scramble key B Program element group (basic service) E, E ₁ , E ₂ , E ₃ Program element group (special service)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H04L 9/14 H04L 9/00 641 H04N 7/167 H04N 7/167 (58) Fields investigated (Int.Cl. ⁷ , DB name) ) H04L 9/08 H04L 9/14 G09C 1/00 H04N 7/167

Claims (5)

(57) [Claims] 1. A method of scrambling or descrambling a packet signal for digital broadcasting, wherein signals of a plurality of program elements that constitute a program are time-division multiplexed in a packet format and are transmitted. When M is classified into a program element group of 2 or more) and different reception qualifications are set for the M program element groups, the allocation of scramble key candidates used in the method is sequentially changed. However, when the scramble key candidates are updated and the program element group is scrambled or descrambled, the total number of the scramble key candidates is set to N (N is an integer of 3 or more), and the scramble key candidates are Regarding allocation, one scramble key candidate among the N scramble key candidates is allocated to scramble key distribution, The remaining N-1 scramble key candidates that have been stored are 1 for each of the M types of program element groups while allowing duplication.
A method for scrambling or descrambling a packet signal, characterized in that it is arranged to allocate the packets one by one. 2. The scrambling or descrambling method of a packet signal according to claim 1, wherein the scrambling key candidate is assigned, in addition to the method according to claim 1, any two kinds in the M kinds of program element groups. A scramble or descramble method for packet signals, wherein different scramble key candidates are assigned to a combination of the above at least within a certain period. 3. The packet signal scrambling or descrambling method according to claim 1 or 2, wherein the M kinds of program element groups are one kind of basic program element group and M-1.
And a special program element group of one kind, regarding the allocation of the scramble key candidate, in addition to the method according to claim 1 or 2, the one basic program element group includes the remaining One scramble key candidate of the N-1 scramble key candidates is assigned, and the N-2 kinds selected in sequence from the special program element group of the M-1 kinds further have the remaining N-2. Of each of the scrambling key candidates, and when there are remaining ((M-1)-(N-2)) special program element groups, the basic program element group is added to the special program element group. A scramble or descramble method for a packet signal, characterized in that the scramble key candidates assigned to the above are assigned redundantly. 4. A scramble key storage unit having N (N is an integer of 3 or more) scramble key storage unit, and a scramble key for distributing the scramble key candidate to each key candidate storage unit of the scramble key storage unit. One of the scramble key candidates stored in the N key candidate storage areas of the scramble key storage means according to the distribution means and the scramble key selection information arranged in the header part of the unprocessed packet signal and read out from the area Scramble key selecting means for selecting one scramble key, and according to the scramble key selected by the key selecting means,
3. A scrambling or descrambling means for scrambling or descrambling the data portion of the unprocessed packet signal in which key selection information for selecting the scrambling key is arranged, respectively. 4. A packet signal scrambling or descrambling device for use in the packet signal scrambling or descrambling method according to any one of claims 1 to 3. 5. The packet signal scrambling or descrambling device according to claim 4, wherein the scrambling or descrambling means is selected at the start point of scrambling or descrambling of each packet of the unprocessed packet signal. A scrambler or descrambler for a packet signal, which is configured to be initialized only by a scramble key and information of a header part and a data part of the packet.