KR20060113091A - Conditional access system in digital receiver - Google Patents

Abstract

A conditional access method of a digital receiver is provided to produce an LST(Local Security Table) and control a de-scrambler through a separate sub key value. An LST besides an EMM(Entitlement Management Message) and an ECM(Entitlement Control Message) is produced. A de-scrambler(20) is controlled by the original key value and another separate sub key value through the LST. The original key value restored from a smart card(10) and a sub key value through the LST are simultaneously applied to the de-scrambler so that the de-scrambler is controlled. The LST is transmitted through a section. The LST is transmitted through a separate channel, not a channel such as the CDMA(Code Division Multiple Access) and the like.

Description

Conditional reception method of digital receiver {Conditional Access System in Digital receiver}

1 is a diagram illustrating a structure of a limited reception system implemented in a digital broadcast receiver according to the prior art.

2 to 5 are diagrams illustrating a method of limiting reception of a digital receiver according to various embodiments of the present disclosure.

-Explanation of symbols for the main parts of the drawings-

10: smart card 20: descrambler

30: LSM

The present invention relates to a limited reception method, and more particularly, to a variety of limited reception method for improving the security and safety in a digital receiver including a terrestrial DMB.

The digitalization trend of broadcasting is progressing rapidly through existing media such as terrestrial, satellite, and cable TV broadcasting, and is revolutionizing the environment of the broadcasting industry.

Among these various media, a new emerging media, digitalization of broadcasting and convergence with communication, is a DMB (Digital Multimedia Broadcasting) service.

When the DMB service is in full swing, it is expected that the conventional techniques applied to terrestrial or satellite broadcasting receivers will also be applied to DMB terminals. In addition, new technologies suitable for the characteristics of mobility are expected to be rapidly developed and applied.

Among these technologies, interest in a conditional access system (CAS), which is called the core of digital broadcasting technology, is increasing.

The CAS is a system for simply granting a right to watch a paid broadcast. The main function of the CAS is to restrict the subscriber to receive the service when the subscriber pays the fee.

In other words, if a user encrypts broadcast content and sends it to the receiver through cable, satellite, terrestrial wave, or the Internet, 'paid service' is possible by granting the right to solve the password only when the receiving party pays the price (view fee). It's a skill that lets you.

Therefore, it is a core system for broadcasters who use paid broadcasting as a source of revenue.

1 is a diagram illustrating a structure of a conditional access system implemented in a digital broadcast receiver according to the prior art.

As shown in FIG. 1, in the conventional Conditional Access System (CAS) technology, a control word (scramble) is encrypted and transmitted on an Entitlement Management Message (EMM) and Entitlement Control Message (ECM) data. The stream to be transmitted is scrambled using the original key value.

The EMM, ECM and the scrambled stream generated as described above are multiplexed in the form of a transport stream and then transmitted to the receiver.

The receiver receives the value, extracts a control word from the EMM and the ECM using a smart card 10, and then scrambles the descrambler 20 through the extracted key value. Descrambled MPEG 2 transport stream.

Such a method has a disadvantage in that the EMM and ECM data carrying the encrypted key value are vulnerable to illegal attacks from outside such as hacking. That is, since the EMM and ECM data are open in the standard, anyone finds that the data has an encrypted key value, and thus there is room for external illegal attack.

Therefore, the development of a method for more securely implementing a paid service is an important issue.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to propose various methods for enhancing security and safety in the limited reception method of a digital receiver.

In order to achieve the above object, the present invention provides a LST in addition to the EMM and ECM in the limited reception method of the digital receiver using the EMM, ECM, the sub-key value different from the original key value through the LST A limited reception method of a digital receiver for controlling a descrambler of the receiver is provided.

The LST is preferably transmitted by using a separate channel different from the channel through which the EMM and ECM are transmitted, and the separate channel may be, for example, a CDMA channel used in a mobile phone.

According to another embodiment of the present invention, in the limited reception method of the digital receiver using the EMM and the ECM, the limitation of the digital receiver using the LST together with the EMM and the ECM as data for generating the key value of the limited reception method. Provide a receiving method.

The LST is characterized in that the encryption data necessary for generating the key value is included.

According to still another embodiment of the present invention, there is provided a limited reception method of a digital receiver for encrypting and transmitting the EMM and ECM to a smart card of the digital receiver in the limited reception method of the digital receiver using the EMM and the ECM.

The encryption means that the raw material is filtered or modified, and the encryption of the EMM and the ECM is performed in the LSM of the digital receiver.

The smart card decrypts the encrypted data to obtain the EMM and the ECM, and decrypts the key value through the EMM and the ECM.

According to still another embodiment of the present invention, in the limited reception method of a digital receiver using EMM and ECM, the key value is decoded using the EMM and ECM, and the decoded key of the receiver is encrypted by encrypting the decoded key value. It provides a limited reception method of a digital receiver to transmit to.

Therefore, according to the present invention, there is an effect of more secure implementation of the paid service in the digital receiver.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

In addition, the term used in the present invention was selected a general term that is widely used at present, but according to the emergence of a new technology, the term that the applicant deemed most appropriate in the present invention was arbitrarily used, and the meaning of the term in the corresponding description. It will be explained clearly. Therefore, in the understanding of the present invention, it is intended that the present invention should be understood as the meaning of terms rather than simple names of terms.

2 is a diagram illustrating a method of receiving a limit in a digital receiver according to a first embodiment of the present invention.

As shown in FIG. 2, the method for receiving a restriction according to the present invention generates a local security table (LST) in addition to the EMM and the ECM, and descrambles the sub-key value different from the original key value through the LST. (Descrambler) 20 to be controlled.

Therefore, the descrambler 20 is controlled by applying the original key value recovered from the smart card 10 and the sub key value through the LST at the same time as used in the conventional limited reception system.

The LST is transmitted by the operator who creates the MPEG 2 transport stream by separately creating the LST.

In this case, the LST may be transmitted using a channel such as a code division muteple access (CDMA) used in a mobile phone, that is, a channel separate from the channel through which the EMM and ECM are transmitted, and thus, security of a restricted reception system. Stability and stability will be improved.

3 is a diagram illustrating a method of limiting reception of a digital receiver according to a second embodiment of the present invention.

In the limited reception method as shown in FIG. 3, the LST is separately transmitted in addition to the EMM and the ECM as in the first embodiment described above with reference to FIG. 2, but the LST is transmitted to the smart card 10 to generate a control word. Done.

That is, the LST includes encryption data necessary for generating the key value together with the EMM and the ECM, and is used as data for generating the key value in the smart card 10.

This method also requires the operator who creates a transport stream (TS) to make the LST separately and transmit it through a section.

4 is a diagram illustrating a method of limiting reception of a digital receiver according to a third embodiment of the present invention.

As shown in FIG. 4, the method according to the third embodiment of the present invention implements a conditional access system using a Local Security Module (LSM) 30 for filtering or modifying EMM and ECM information. .

That is, the security is further enhanced by encrypting the EMM and ECM data having information on the encrypted key value once more. For reference, encryption means that the original data is filtered or modified as described above.

As such, the information encrypted through the LSM 30 is decrypted through the smart card 10 to extract a key value, and descrambles the scrambled transport stream in the descrambler 20 through the key value.

In this case, the smart card 10 includes information on the process of encrypting through the LSM 30 to decrypt the data encrypted through the LSM 30 to obtain EMM and ECM information, and the decrypted EMM. The original key value is decoded through the ECM information.

5 is a diagram illustrating a method of receiving a limit in a digital receiver according to a fourth embodiment of the present invention.

As shown in FIG. 5, the method of receiving a restriction according to the fourth embodiment of the present invention is different from the method of modifying (encrypting) EMM and ECM, which are data before generating a key value, in the third embodiment. It is a method to implement restriction reception by newly modifying the key value generated from the code.

To this end, the local security module (LSM) 30 is placed in front of the descrambler 20, and the key value received after being decrypted from the smart card 10 through the LSM 30 is received and encrypted.

The encrypted key value is input to the descrambler 20, and the descrambler 20 descrambles the encrypted key value and descrambles the transport stream which is scrambled with the original key value.

This method essentially blocks illegal attacks from the outside on the decrypted key value, and has the advantage of easy control at the receiving side.

The present invention is not limited to the above-described embodiments, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the invention pertains, and such modifications are within the scope of the present invention.

The limited reception method of the digital receiver according to the present invention described above has the following effects.

First, it is effective to implement paid services more securely in digital receivers.

Second, there is an effect that can be usefully used for the development of paid data broadcasting services or paid content in the future.

Claims (10)

In the limited reception method of the digital receiver using EMM, ECM, The method of claim 1, further comprising generating an LST in addition to the EMM and the ECM, and controlling the descrambler of the receiver with a sub key value different from the original key value through the LST. The method of claim 1, The LST is limited reception method of a digital receiver characterized in that the transmission using a separate channel different from the channel through which the EMM, ECM is transmitted. The method of claim 2, And the separate channel is a CDMA channel. In the limited reception method of the digital receiver using EMM, ECM, And LST together with the EMM and ECM as data for generating a key value of the conditional access method. The method of claim 4, wherein And the LST includes encryption data necessary for generating the key value. In the limited reception method of the digital receiver using EMM, ECM, The method of claim 1, wherein the EMM and ECM are encrypted and transmitted to the smart card of the digital receiver. The method of claim 6, And the encryption is filtering or modifying original data. The method of claim 6, And the encryption of the EMM and the ECM is performed in the LSM of the digital receiver. The method of claim 6, The smart card decrypts the encrypted data to obtain the EMM and ECM, and decrypts a key value through the EMM and ECM. In the limited reception method of the digital receiver using EMM, ECM, Decode the key value using the EMM, ECM, And receiving the decoded key value and transmitting the encrypted key value to the descrambler of the receiver.

Images