KR100435918B1 - Method for encryption recording a data in digital broadcasting program - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for data encryption and recording in a digital broadcast program. The present invention relates to a digital broadcast receiver having a PVR (Personal Video Recorder) function, which descrambles and decodes a specific scrambled digital broadcast program, After transmitting and outputting to the same A / V device, the descrambled data is encrypted again and then recorded and stored on the hard disk, depending on the current load of the CPU, in whole or in part of the descrambled data. By selectively encrypting and storing the data, it is a very useful invention that it is possible to prevent the encryption operation error or other functions and operations from being suspended due to the overload of the central processing unit. .

Description

{Method for encryption recording a data in digital broadcasting program}

The present invention provides a set-top box having a PVR (Personal Video Recorder) function for receiving and transmitting a digital broadcast program to an external connection device such as a television, and outputting the same to a large capacity recording medium such as a hard disk (HDD). In a digital broadcast receiver such as a set top box), the present invention relates to a data encryption recording method for a digital broadcast program recorded and stored on the hard disk.

In conventional analog television broadcasting, a video signal is transmitted through radio wave and wired cable by AM modulation or FM modulation, but recently, digital television broadcasting has been developed according to the development of digital technologies such as digital image compression and digital modulation / demodulation. Standardization and commercialization are rapidly progressing, and conventional terrestrial, satellite, and cable broadcasting are also being digitized based on the Moving Picture Experts Group (MPEG).

On the other hand, the digital broadcast as described above, according to the development of digital video / audio compression technology and digital transmission technology can provide a higher quality broadcast service than the analog broadcast signal service, in particular multiplexing and transmitting a plurality of broadcast programs in the same bandwidth And it has an advantage that can greatly increase the interoperability with digital communication media and digital storage media.

In the digital broadcast, a plurality of broadcast programs encoded on the basis of MPEG are multiplexed and transmitted in a transport stream, and the transport stream is a digital receiver such as a set-top box (STB) installed at a receiving side. A plurality of broadcast programs received by the broadcast receiver and included in the transport stream are demultiplexed.

Therefore, only one broadcast program desired by the user can be selected, and in a digital broadcast receiver such as the set-top box, the selected broadcast program is restored to the original audio and video signal by using a decoder provided in the receiver. After that, the output is transmitted to an A / V output device such as a general television.

Recently, a large capacity hard disk (HDD) is additionally provided in a digital broadcast receiver such as the set-top box, and a program recorded on the hard disk is stored and stored on the hard disk. It is expected that a digital broadcast receiver having a PVR function that can play and output a broadcast program recorded and stored on the hard disk will be widely distributed and distributed according to a user's request. In order to prevent unauthorized copying of paid broadcast programs, the receiver descrambles a specific scrambled digital broadcast program and transmits the output to an A / V device such as a general television. The descrambled digital broadcast program using a conventional encryption scheme, Using the word 'XOR', such a general encryption method to be referred to as 'DES' or 'IDEA', and so that the copyright protection for then re-encrypts (Encryption), by writing to the hard disk, a pay-TV program done.

However, when the descrambled digital broadcast program is encrypted again and stored on a hard disk as described above, a significant load is applied to the central processing unit (CPU) included in the digital broadcast receiver. In this case, an error occurs or other functions and operations are suspended. However, an efficient solution is not yet provided, and thus, an urgent need for the solution is urgently needed.

Accordingly, the present invention was created in view of the above situation, and in a digital broadcast receiver equipped with a PVR function, descrambles and decodes a specific scrambled digital broadcast program to an A / V device such as a general television. In addition to transmitting and outputting, the descrambled data is encrypted again and then recorded and stored on the hard disk, and according to the current load of the central processing unit, all or part of the descrambled data is selectively encrypted and recorded. It is an object of the present invention to provide a method for recording and encrypting data in a digital broadcasting program to be stored.

1 schematically shows a correlation between a general elementary stream, a PES stream and a transport stream,

2 illustrates header information included in a general transport packet (TSP),

3 illustrates a configuration of a digital broadcast receiver to which the present invention is applied.

4 is a flowchart illustrating an operation of a data encryption recording method in a digital broadcasting program according to the present invention;

5 is a table showing information on an encrypted recording mode according to the present invention.

※ Explanation of code for main part of drawing

10: demultiplexer 11: parser

12: buffer memory 13: decryption unit

14 hard disk 15 central processing unit

16 descrambler 17 encryption unit

18: decoder

According to an aspect of the present invention, there is provided a method of encrypting data in a digital broadcast receiver, the method comprising: receiving a transport stream through a digital broadcast system; Extracting a portion of the transport stream; Encrypting the extracted data; And storing the transport stream including the encryption part in four steps.

Hereinafter, a preferred embodiment of a data encryption recording method in a digital broadcast program according to the present invention will be described in detail with reference to the accompanying drawings.

First, in general digital broadcasting, as shown in FIG. 1, an elementary stream such as video, audio, or program specific information (PSI) is matched to the overall transport stream TS. Properly, the program elementary stream header is created, the payload is configured to match the contents of the PES header, and the PES packetizing operation for generating the PES packet is performed. The video elementary stream is converted into a video PES packet and the audio elementary stream is converted into an audio PES packet.

On the other hand, what is a PES stream. Meaning a series of PES packets, one PES stream is composed of only the same kind of PES packets, and a unique ID (ID) for identifying the same is recorded in the header of the PES packet, which is recorded in the PES header. The unique ID, i.e., the Stream ID, is a type of data recorded in the payload of the PES packet.

The PES packet configured as described above is reconstructed into a transport packet (TSP) having a predetermined recording size, for example, 188 bytes, wherein the contents of the PES packet are determined. The payload of the transport packet is all divided and recorded. The header of the transport packet includes program information constituting the transport stream, time information of the program, and various control information for controlling the entire transport stream. Are recorded to include.

Therefore, the elementary stream of video, audio, or program specification information data is recorded in the payload of the PES packet, and unique IDs and control information for indicating the type of data recorded in the payload of the PES packet are PES packets. The PES packet is divided into the payload of the transport packet (TSP) and recorded, while various control information for controlling the PES stream recorded in the payload of the transport packet as a whole are It is recorded in the header of the transport packet.

Meanwhile, when PES packet data recorded in the payload of the transport packet is scrambled for copyright protection and unauthorized copy protection, 2-bit transport scrambling control information (Transport_Scrambling_Control) information recorded in the header of the transport packet is recorded. 2 has a value other than at least '00', for example, a value of '01' indicating that it is " scrambled " by User Defined.

Accordingly, in the digital broadcast receiver applied to the present invention, when the value of the 2-bit transport scrambling control information recorded in the header of the transport packet is checked, and the value is not '00', for example, If it has a value of '01' indicating that it is scrambled by user definition, it is determined that the PES packet data recorded in the payload of the transport packet is scrambled to prevent unauthorized duplication.

After descrambling the scrambled data, the scrambled data is decoded into original audio and video data, transmitted and output to an A / V device such as a general television, and the scrambled data is again encrypted. In this case, the digital broadcast receiver selectively encrypts all or part of the descrambled data according to the current load of the central processing unit, and stores the data on the hard disk. .

3 shows a configuration of a digital broadcast receiver to which a data encryption and recording method according to the present invention is applied. The digital broadcast receiver includes a transport stream (MPTS: Multi) in which multiple digital broadcast programs are multiplexed. A demultiplexer 10 for selectively outputting a transport stream (SPTS: Single Program TS) of any one of Program TS); A parser (11) for separately outputting 188-byte transport packets constituting the one transport stream and header information of the transport packet; A buffer memory 12 for temporarily storing transport packets outputted through the parser; A descrambler 16 for descrambling the encrypted data scrambled and recorded at the payload of the transport packet read out from the buffer memory; A decoder (18) for restoring and outputting the descrambled data to original video and audio data; An encryption unit (17) for encrypting the descrambled data and storing the data on the hard disk (17); A decryption unit 13 for decrypting encrypted data read from the hard disk and temporarily storing the encrypted data in the buffer memory; In addition, a central processing unit 15 for controlling the operation of each of the components may be included.

Meanwhile, the CPU 15 charges the transport packet according to the value of the transport scrambling control information recorded in the header information of the transport packet separately output through the parser 11. It is checked whether or not the PES packet data recorded in the load is scrambled. When the scrambled result is checked, the descrambler 16 is controlled to operate so that the encrypted data recorded in the payload of the transport packet is decoded. After being scrambled, the decoder 18 restores the original video and audio data.

In addition, after detecting and confirming the load amount of the operating system (OS) and the plurality of application programs (AP # 1 to AP #n) running in the CPU, the operation of the encryption unit 17 is controlled according to the load amount. Encrypting the entire descrambled data, or selectively encrypting only a part of the descrambled data and storing the data on the hard disk 14 so that the encryption operation may be performed due to an overload of the central processing unit. It is possible to prevent the occurrence of an error or the suspension of other functions and operations in advance, which will be described in detail as follows.

FIG. 4 is a flowchart illustrating a method of recording and encrypting data in a digital broadcast program according to the present invention. As described above, the CPU 15 operates and controls the demultiplexer 10. After selecting and receiving any one MPEG transport stream, transport packets constituting the MPEG transport stream are temporarily stored in the buffer memory 12 (S10).

In addition, the value of the transport scrambling control information of 2 bits recorded in the header information of the transport packet separately output through the parser 11 is checked (S11). If the value is a value other than at least '00 (not Scrambled '), for example, a value of' 01 'indicating that it is " Scrambled " by user definition, the PES packet recorded in the payload of the transport packet. It is determined whether the data have been scrambled (S12).

On the other hand, when it is confirmed that the scrambled process is performed as described above, the central processing unit 15 controls the descrambler 16 to allow the scrambled PES packet data to be descrambled, thereby providing the decoder ( 18, the original video and audio data is transmitted and output to the general television (S13).

In addition, the current load amount by the operating system (OS) and the plurality of application programs (AP # 1 to AP #n) running in the central processing unit 15 is detected (S14), and is set in advance according to the load amount. Multiple encryption recording modes (Encryption_Mode), for example, as shown in Figure 5, when the current load in the central processing unit is 90% or more, the data to be encrypted in the encryption unit 17 I-picture or geo The first mode (Mode # 1) that specifies to limit the GOP) control data is selected and determined, and if the current load is within the range of 80% to 89%, the encryption unit 17 controls the data to be encrypted. Selecting and determining the second mode (Mode # 2) that specifies to restrict the data only, and if the current load is within the range of 70% to 79%, the data to be encrypted by the encryption unit 17 is I-picture. In addition When selecting the third mode (Mode # 3) that specifies to limit only the geo-data only, and if the current load is within the range of 60% to 69%, the data to be encrypted by the encryption unit 17 is the video full data The fourth mode (Mode # 4) that specifies to be restricted to only be selected. If the current load is 59% or less, the fifth mode in which the data to be encrypted is designated by the encryption unit 17 as all data. It is determined to select (Mode # 5) (S15).

For reference, the encryption recording mode may be arbitrarily variable or additionally set so that the more the load of the central processing unit is, the more the encryption is performed, and the greater the load is, the less the encryption is.

On the other hand, when the encryption recording mode is determined through the above process, the CPU 15 transmits a corresponding control signal (Mode_CTL) to perform the encryption operation corresponding to the encryption recording mode, the encryption unit ( 17), and the encryption unit selects a series of encryption recording operations for encrypting the data output through the descrambler 16 again in an encryption recording mode corresponding to the control signal. The recording method is stored in the hard disk (S16), wherein the encryption method used in the encryption unit is a conventional encryption method, for example, a general encryption method called 'XOR', 'DES' or 'IDEA' is used. Can be.

In the encryption unit 17, additional identification information for identifying the encryption recording mode, for example, encryption recording mode identification information (Encryption_Mode_ID) having a recording size of 3 bits, is stored in the hard disk 14. Further recording is performed in association with the encrypted data recorded and stored in step S17.

Therefore, when the data encrypted and recorded and stored by the various encryption recording modes as described above is read and reproduced from the hard disk 14, the decryption unit 13 reads out identification information (Encryption_Mode_ID) recorded in association with the data. It is possible to confirm and perform a decryption operation corresponding to the encrypted recording mode.

On the other hand, when the value of the transport scrambling control information is '00 (not Scrambled) ', that is, when it is determined that the PES packet data recorded in the payload of the transport packet is not scrambled, the center is determined. In the processing device 15, the descrambling operation in the descrambler 16 is stopped, and the original video and audio data are transmitted and output to the general television through the decoder 18 (S18).

Then, the encryption operation in the encryption unit 17 is stopped to perform a data general recording operation for recording the scrambled data as unencrypted data on the hard disk (S19).

Above, the preferred embodiment of the present invention described above, for the purpose of illustration, within the spirit and scope of the present invention disclosed in the appended claims, and further various other embodiments, modifications, Replacement or addition may be possible.

The data encryption and recording method of the digital broadcast program according to the present invention, which is constructed and constructed as described above, descrambles and decodes a scrambled specific digital broadcast program in a digital broadcast receiver equipped with a PVR function, such as a general television. After transmitting and outputting to the A / V device, the descrambled data is encrypted again and then recorded and stored on the hard disk, and all or part of the descrambled data is stored according to the current load of the central processing unit. By selectively encrypting and storing the data, it is a very useful invention that the encryption operation error can be prevented due to the overload of the central processing unit, or other functions and operations can be prevented in advance.

Claims (6)

In the data encryption recording method in a digital broadcast program, Receiving a transport stream through a digital broadcasting system; Extracting a portion of the transport stream; Encrypting the extracted data; And And encrypting the transport stream including the encryption portion in four steps. The method of claim 1, And if the transport stream received in step 1 is an encrypted stream, further comprising being descrambled by a descrambler. The method of claim 1, The second step, data encryption and recording method for a digital broadcast program, characterized in that for extracting the header of the minimum video data to encrypt the transport stream. The method of claim 1, In the second step, the transport stream extracted according to the system load is different, and the load of the system is compared with the maximum system processing capacity versus the corresponding system load, and the larger the load of the system, the lower the encryption. Selecting and determining the data encryption recording method in the digital broadcasting program. The method of claim 4, wherein The encrypted recording mode may include at least one of the entire transport stream data, video data, I-picture or geofi data, video control data, and I-picture or geofi control data for selecting and encrypting the data. An encrypted data recording method in a digital broadcast program, characterized by comprising an encrypted recording mode. The method of claim 4, wherein And additionally recording identification information for identifying the encrypted recording mode.