KR100487246B1 - Method for preventing illegal relay broadcast - Google Patents

Abstract

The present invention relates to a technique for preventing illegal retransmission by receiving a broadcaster's broadcast, and a method for detecting whether a user continuously watches the same channel for a predetermined time without switching channels in order to distinguish between a normal subscriber and an illegal retransmitter. I use it.

According to the illegal retransmission prevention method according to the present invention, if the user continuously watches the same channel for a predetermined time, the set-top box lock function operates when the pin code value of the set-top box is changed and the power is turned on again, considering the illegal channel retransmission. Turn off the power after setting.

Description

How to prevent illegal resend of your set-top box {METHOD FOR PREVENTING ILLEGAL RELAY BROADCAST}

The present invention relates to a method of limiting reception of a set top box, and more particularly, to a method for preventing illegal retransmission so that only a normal paid subscriber can receive a broadcast using the set top box.

Today's TV broadcasts are shifting from analog to digital. Most of the world's major countries will start digital broadcasting around 2000, and will run parallel to analog broadcasting. The standard of digital TV broadcasting can be divided into European DVB (Digital Video Broadcasting) method and American Advanced Television Systems Committee (ATSC) method.

As digital multimedia services are expected to increase rapidly in the digital broadcasting environment, copyright protection and management technologies for multimedia contents should be solved first in order to effectively protect and manage the interests of service providers and the rights of consumers. In particular, digital data can be easily copied in large quantities and can be quickly and widely transmitted and distributed. In addition, the copied digital works are of the same quality as the original, and have high flexibility for editing and compositing. In addition, providing a variety of services such as music, video, video, etc. due to the recent rapid development of transmission technology such as satellite communication, network, etc. is convenient and useful for service users, but on the contrary, it provides a threat to stably providing various multimedia contents to copyright owners. This is because most of the works are digitized, and large-capacity, high-performance general-purpose personal computers are developed to easily copy, edit, and distribute multimedia contents. Therefore, research to protect the copyright of multimedia works is indispensable.

The features of digital broadcasting are summarized as multichannel, high quality and multifunctional. In particular, with the development of multiplexing technology, video, audio, and data can be bundled and transmitted at the same time regardless of contents and size, and a return channel through a modem is formed for interactive service. Accordingly, digital data broadcasting can overcome the limitations of existing analog broadcasting and provide high value-added multimedia services to viewers. However, in the integrated broadcasting of digital data, if mutual security is not established between the transmitting side and the receiving side, the commercial structure of the broadcasting collapses. In addition, broadcasters are paying broadcasts such as pay-TV and pay-per-view, which provide high quality broadcasting services to subscribers and collect viewership fees from services that rely on existing advertising revenues through the activation of multi-channel and professional channels. We want to provide the service and also to protect the various multimedia data sent out so that only authorized subscribers with legitimate reception rights can receive it. The CAS was developed to solve this problem.

Digital broadcast receivers include Free-To-Air (FTA), Conditional Access System (CAS), and Common Interface (CI) .FTA refers to a receiver that can be viewed by anyone in the public for free. This system refers to a system that allows subscribers with legitimate viewing rights to receive a specific program, and CI is a CAS function that allows users to watch paid broadcasting. It is a digital video broadcasting (DVB) standard defined as an interface defined to perform the corresponding CAS function when inserted into the CI slot.

 2 is a block diagram showing the configuration of a CAS, that is, a conditional access system. CA system is a core system of broadcasting system for digital broadcasting pay service along with subscriber management system. This ensures that subscribers can receive the services they want accurately and conveniently, protects their income by preventing illegal viewing, and provides various marketing materials such as subscriber's viewing tendency to enable broadcasting based on viewers. System.

A conditional access system requires the following functions. Scrambling and descrambling functions to protect the original signal from unauthenticated recipients, entitlement control functions and entitlements to be interpreted only to the specific subscriber who paid the fee. Entitlement management functions are essential.

Scrambling scrambles the multimedia data to be transmitted in a predetermined rule so that the scrambled data cannot be viewed by a receiver without receiving permission. The scrambling modifies a signal using a control word (CW). Encryption is a method to protect the control word transmitted with the scrambled signal to be sent to the receiver's decryptor. The transmitter and receiver must have the same secret key so that the descrambling process is accurate. Can be performed. In the process of delivering such a secret key, a smart card is used to deliver the secret key to the user in order to increase security.

The entitlement control function encrypts a control word and sends it to an entitlement control message (ECM), which is sent to the receiver periodically for security purposes. Each time a new control word is encrypted. In addition to the encrypted control word, the ECM includes control parameters, and all receivers can receive the transmitted ECM. Among them, the smart card is compared with the authorization parameter of the control variable and the receiver. Decrypt the control word using the secret key inside and descramble the received program using it.

The entitlement management function is an entitlement or update of a receiver. The entitlement management system generates and encrypts an entitlement management message (EMM) and transmits the entitlement management message (EMM) to the receiver through a transport stream (TS). The EMM performs the function of entitlement or renewal in the smart card, which is the security device of the receiver, and the function of changing the pin code of the smart card.

Eligibility is delivered through the EMM. The sender must send the program's authentication key and eligibility to the legitimate recipient of the subscription. The authentication key is encrypted using the recipient's unique distribution key, and then the EMM is generated by the EMM generator along with the authentication variable. The receiver checks whether the EMM has been sent to itself, checks the digital signature, and goes through the EMM authentication process. If all is OK, the authentication key is decrypted using its own distribution key and stored in the storage with the authentication variable.

The receiving principle of the program is as follows. In the transmitter, if the receiver has already received the authentication variable and the authentication key through the EMM, the transmitter encrypts the control word using the authentication key and then generates an ECM including the control variable through the ECM generator. ECM adds digital signatures to prevent tampering with messages. The source program is controlled by control variables and scrambled using the output of the pseudo random binary sequence (PRBS) and transmitted to the receiver.

The receiver performs the ECM authentication process by checking the digital signature to confirm that the contents of the ECM have been tampered with. If there is no error, the encrypted control word part is sent to the decryptor and the control variable is sent to the comparator. The comparator compares the stored authentication variable with the control variable to check if the condition is correct, and if the condition is correct, passes the authentication key to the decryptor to decrypt the control word. The decrypted control word is used to descramble the program using the output of the PRBS controlled by it.

In pay-TV receivers, in which a specific broadcast is encrypted so that a viewer can watch a certain amount of money, if the illegal broadcaster retransmits the encrypted pay-TV by using a set-top box, it may cause a huge loss to the broadcaster. Therefore, a method for preventing such illegal unauthorized retransmission will be required.

Accordingly, an object of the present invention is to provide a method of preventing a broadcast of a digital broadcasting company from receiving and illegally retransmitting the broadcast.

In order to achieve the above object, the method of the present invention includes checking whether the same channel is watched without changing the channel for a predetermined time, and setting the pin code value of the set-top box when there is no channel switching for the predetermined time. Or changing to an arbitrary value, setting the lock function of the set-top box to operate when the power is turned on, and forcibly turning off the power.

Here, the CAS box may further include changing a pin code of the smart card after the pin code value changing step of the set top box. Meanwhile, the broadcaster may further include changing a pin code to operate the set top box again.

Hereinafter, a method for preventing illegal retransmission of a set top box according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart of a method for preventing illegal retransmission according to an embodiment of the present invention. In the present invention, as a method of detecting illegal retransmission, a method of checking whether the set-top box is watching the same channel without changing the channel for a predetermined time or more is used. However, the illegal retransmitter is focused on the fact that there is a characteristic of using it fixed to a specific channel. Therefore, if there is no channel change for a certain time, that is, a normal viewer exceeds the maximum time for changing the channel, it can be inferred that it is generally used by an illegal resender.

The channel change check is performed in the following manner. First, the variable is set to 0, and the variable is increased by 1 every set time in the set-top box, and the variable is set to 0 again when there is a channel change. If there is no channel change over a certain time, the variable will continue to increase and reach the determined value. In this way, it is checked whether there is no channel change over a certain time.

If it is detected that the channel of the set-top box has not changed for a certain period of time, it is regarded as the use of an illegal re-sender, and the pin-code value of the set-top box is changed to a predetermined value or an arbitrary value. If it is a box, the pin code value of the smart card is also changed. (103) If the pin code is changed to a predetermined value, the user can unlock the lock function and operate the set-top box by informing the user of the pin code. If the PIN code is changed to a value, the lock function cannot be unlocked because the PIN code is not known unless the operator changes the pin code by contacting the provider and creating an EMM.

After changing the pin code value, set the set-top box to operate the lock function when power is turned on (104), and then forcibly turn off the power of the set-top box (105). The set-top box lock function is activated.

The pin code is used to unlock the lock. In other words, you need to know the pin code to unlock the set-top box to operate the set-top box. When the lock function is turned on and the set-top box is operated, a pop-up menu that prompts for a pin code is displayed to compare the pin code received with the pin code stored in the set-top box or smart card. It is the function to operate set-top box only. If you do not know the pin code, you can no longer proceed from the menu that receives the pin code, it is impossible to watch the broadcast using the set-top box. Therefore, if it is judged to be illegal retransmission, after changing the pin code and setting the lock function, if the power is forcibly turned off, the user cannot watch the broadcast with the set-top box because the pin code is not known when the power is turned on again.

When a normal subscriber changes the pin code value due to the above procedure and cannot use the set-top box, the broadcaster informs the subscriber of the pin code, if the subscriber changes to the designated pin code. You can use a box. On the other hand, if it is changed to an arbitrary pin code, when the broadcaster generates and broadcasts an EMM that can change the pin code, the set-top box receives it, enters it into the smart card, and the smart card changes the pin code. In this way, the newly changed pin code can be unlocked and the set-top box can be used again.

According to the method of preventing illegal retransmission of the set-top box according to the present invention, it is possible to effectively prevent illegal retransmission through a relatively simple method of checking whether there is no channel change for a predetermined time.

1 is a flowchart of a method for preventing illegal retransmission according to an embodiment of the present invention.

2 is a block diagram showing the configuration of a CA.

Claims (5)

Checking whether the user is watching the same channel without switching the channel for a predetermined time; And If there is no channel change for a predetermined time as a result of the check, the set-top box is operated when the pin code of the set-top box is changed, and the lock function of the set-top box is set, and a different pin code is input when the power is turned on. And forcibly turning off the power after preventing the illegal retransmission of the set-top box. The method of claim 1, wherein the CA system further comprises the step of changing the PIN code of the smart card when there is no channel switching for a predetermined time. Prevention method. The method of claim 1 or 2, wherein the changed pin code is a specific value. The method of claim 1 or 2, wherein the changed pin code is an arbitrary value. The method of claim 1, further comprising the step of changing the pin code by the broadcaster to operate the set-top box again.