KR100950599B1 - Method for applying downloadable conditional access system and apparatus thereof - Google Patents

Abstract

PURPOSE: A DCAS applying method and a device thereof are provided to apply DCAS(Downloadable Conditional Access System) to an existing set top box without the modification of hardware by supplying an SM(Secure Micro) module with a software type or USB type. CONSTITUTION: A DCAS server transmits a DCAS host image to a set top box(S602). The set top box stores a DCAS host module(S604). The set top box stores a DCAS interface(S606). The DCAS server transmits an SM module to the set top box(S608). Depending on rebooting of the set top box, DCAS initialization process is performed(S610). The DCAS server transmits CAS(Conditional Access System) client and user authentication secret information to the set top box(S612).

Description

Method for applying Downloadable Conditional Access System and Apparatus

The present invention relates to a method and apparatus for applying a DCAS, and a method for applying a DCAS without a hardware change of an existing OpenCable based set-top box, and an open cable-based set-top box apparatus to which a DCAS is applied.

Digital conversion of broadcasting is taking place worldwide, and the digitalization of broadcasting technology and systems has already been completed.

Unlike analog content, digital content can not only be completely copied, but also easy to edit and distribute. Therefore, it is essential to restrict and protect access to content.

For this reason, a conditional access system (hereinafter referred to as "CAS") has been proposed to allow only legitimate subscribers to access the content.

The CAS, in conjunction with the Subscriber Management System (SMS), handles the receipt and playback of specific programs only to authorized subscribers.

In a typical CAS, the headend scrambles content and data using a control word (CW), where the control word is encrypted with an authentication key and the authentication key is encrypted with a distribution key.

When a receiving end such as a set-top box receives a scrambled transport stream, the receiving end decrypts the authentication key with the distribution key, obtains a control word with the decrypted authentication key, and descrambles the scrambled transport stream through the obtained control word to view the form. The signal is output as.

On the other hand, the OpenCable method, which is an American standard of cable broadcasting, stipulates that smart card and POD module containing subscriber information can be separated / installed from the set-top box, so that even if the subscriber changes the cable station, the POD module Replace only so that the old set-top box can be used as it is.

Therefore, in the conventional open cable-based set-top box, as shown in FIG. 1, the transport stream (scrambled content) received from the tuner 100 is an independent POD module (Point of Deployment) 104 connected to the smart card 102. Is entered.

Here, the POD module 104 is a CAS module of the receiving end that processes the security function and the reception restriction function, and performs descrambling of the received transport stream using the subscriber information stored in the smart card 102.

The stream descrambled by the POD module 104 is reproduced through a decoder included in the system-on-chip (Soc) 106.

A typical set-top box includes a transmission processor for descrambling a transport stream in the system on chip 106. However, in the related art, a descramble in a POD module 104 that is independent of the system on chip 106 is not used. Let this be done.

In the conventional open cable-based set-top box, the POD module 104 has a built-in CAS module of a specific operator, and thus there is a problem that the set-top box itself should be replaced when the CAS operator is changed in the future.

In order to solve this problem, DCAS (Downloadable CAS) has recently been proposed.

DCAS uses a method of downloading and running a CAS client provided by an operator in a set-top box referred to as a DCAS host from a DCAS authentication server onto a Secure Micro (SM) module in the DCAS host.

However, until now, the general method proposed for applying DCAS is to store the SM module in a separate chip that guarantees security and mount it on the set-top box in the form of on-board. Therefore, the hardware change of the conventional open cable-based set-top box is required to apply the DCAS.

As described above, the hardware change for the application of DCAS is based on a new set-top box, and this requirement causes inconveniences because the subscriber has to replace the existing set-top box to use the DCAS.

The present invention is to propose a method and apparatus for applying a DCAS that can change the set-top box to a DCAS host without changing the hardware of the conventional open cable-based set-top box as described above.

In order to achieve the above object, according to an embodiment of the present invention, in the method of applying a downloadable conditional access system (DCAS) to an open cable-based set-top box, for a DCAS host including a DCAS host module Downloading an image; Downloading a Secure Micro (SM) module to send and receive messages to and from the DCAS host module; And downloading a CAS (Conditional Access System) client performing a function for descrambling the transport stream from the DCAS server, wherein the transport stream is transmitted based on the DCAS host module and the SM module without passing through the POD module. A method of applying DCAS descrambling in a processor is provided.

According to another aspect of the invention, a tuner for receiving a scrambled transport stream; Independent POD (Point of Deployment) module to work with the smart card according to the open cable set-top box standard; A System on Chip including a decoder and a transmission processor; A memory configured to store an image for a DCAS host including a downloadable conditional access system (DCAS) host module and a secure micro (SM) module to establish a connection with the DCAS host module; And controlling a download of a Conditional Access System (CAS) client communicating with a DCAS server based on the stored SM module to perform a function for descrambling the transport stream, and based on the DCAS host module. There is provided a DCAS application apparatus including a control unit for controlling to be descrambled in the transmission processor without passing through the POD module.

According to another aspect of the invention, a tuner for receiving a scrambled transport stream; Independent POD (Point of Deployment) module to work with the smart card according to the open cable set-top box standard; A System on Chip including a decoder and a transmission processor; A memory for storing a DCAS host image and a DCAS host module including a downloadable conditional access system (DCAS) host module; A security processor of a universal serial bus (USB) dongle type, in which a secure micro (SM) module, which is connected to the DCAS host module, is stored; And controlling a download of a conditional access system (CAS) client communicating with a DCAS server based on the stored SM module to perform a function for descrambling a transport stream, wherein the transport stream is controlled by the POD based on the DCAS host module. Provided is a DCAS application apparatus including a control unit configured to control descrambling in the transmission processor without passing through a module.

According to another aspect of the present invention, a method for applying a downloadable conditional access system (DCAS) in an open cable (OpenCable) set-top box and a server connected through a network, the set-top box for a DCAS host including a DCAS host module Transmitting an image; Transmitting a SM (Secure Micro) module for transmitting and receiving a message with the DCAS host module to the set-top box; And transmitting a CAS (Conditional Access System) client performing a function for descrambling a transport stream to the set-top box after authenticating the set-top box in which the SM module is stored. Provided is a method of applying a DCAS based on a DCAS host module and an SM module to descramble the transport stream in the transport processor without passing through the Point of Deployment (POD) module.

According to the present invention, since an SM (Secure Micro) module that performs the DCAS protocol and generates and stores keys and secret information is provided in a software type or a USB type, an existing set-top box can operate as a DCAS host without changing hardware. have.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

 Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate a thorough understanding of the present invention, the same reference numerals are used for the same means regardless of the number of the drawings.

2 is a diagram illustrating a DCAS system according to an embodiment of the present invention.

As shown in FIG. 2, a head-end 200, a downloadable conditional access system (DCAS) server 202, and a set-top box (STB) 204 may be included.

The headend 200 receives content from a content provider and encodes the content in a preset format.

In addition, the headend 200 performs scrambling (encryption) of content according to a preset Conditional Access System (CAS) algorithm, and transmits the scrambled content (Scrambled Transport Stream) to the set-top box 204.

According to the present invention, the set-top box 204 is a set-top box conforming to the open cable standard, which is an American cable broadcasting standard, and DCAS is applied to the set-top box 204 to operate as a DCAS host.

The DCAS server 202 transmits and receives a predetermined message with the set-top box 204, and performs security management of the message.

Although the DCAS server 202 is shown separately from the headend 200 in FIG. 2, this is for convenience of description only, and the DCAS server 202 may belong to the infrastructure of the headend 200. It will be obvious to you.

According to the present invention, the DCAS server 202 establishes a connection with the open cable-based set-top box 204 and transmits an image for the DCAS host for the set-top box 204 to operate as a DCAS host.

Here, the image for the DCAS host is a modified platform code, middleware (OpenCable Application Platform Stack) and porting layer for changing the set-top box 204 to the DCAS host, as shown in FIG. And DCAS host module.

Here, the modified platform code, middleware, and porting layer may include a DCAS interface for supporting communication with the DCAS host module.

Platform code, also known as glue code, is the code that connects the porting layer and hardware.

The porting layer defines a platform-independent middleware-side application program interface (API), and provides an API for hardware control such as a real time operating system installed in the set-top box 204, a CPU, and a decoder.

On the modified porting layer, a POD porting layer (POD PL) for a POD module that interworks with a smart card in the open cable-based set-top box 204 is removed, and a DCAS interface is added.

Meanwhile, the DCAS server 202 according to the present invention transmits an SM (Secure Micro) module to the open cable-based set-top box 204 in which the DCAS host module is installed.

The SM module executes the DCAS protocol, generates and stores key and secret information for descrambling (descrambling), and SM client related data and code such as a CAS client and a Digital Rights Management (DRM) client as described below. Save it.

4 is a diagram illustrating components of the DCAS. Referring to FIG. 4, the SM module 400 may include a DCAS monitor 402 and an SM bootloader 404.

The DCAS monitor 402 performs message routing between the SM boot loader 404 or CAS client and the SMD (SM Driver) 416 of the DCAS host module 410.

The SM boot loader 404 checks an SM client such as a CAS client and transmits and receives a message for authentication with the DCAS server 202 while the SM module is driven.

The DCAS host module 410 may include a conditional access network handler (CAN) 412, a DCAS manager 414, and a SMD driver 416.

The conditional access network handler 412 controls the connection establishment with a network capable of supporting CAS, and controls the network processing environment required for a particular network to send a message to a DCAS host to process the message.

The DCAS manager 414 manages all DCAS functions in the set top box 204 corresponding to the DCAS host. The DCAS manager 414 interfaces with the SMD 416 and the conditional access network handler 412 and controls the connection setup for the SM bootloader 404 and CAS clients. In addition, the DCAS manager 414 performs routing, filtering, and queuing functions of the messages destined for the SM module 400.

Meanwhile, in the above description, the open cable-based set-top box 204 downloads the image and the SM module for the DCAS host from the DCAS server 202.

However, one of ordinary skill in the art understands that the SM module including the image and software for the DCAS host may be downloaded to the memory of the open cable-based set-top box 204 using near field communication (eg, USB communication method) without being limited thereto. Should.

According to the present invention, since the SM module 400 for DCAS support is provided by software instead of an on-board chip, the existing open cable-based set-top box can be used as it is.

As described above, the set-top box 204 in which the download of the DCAS host module 410 and the download of the SM module 400 are completed performs a function as a DCAS host, after which the DCAS server 202 according to the present invention is a set-top box. 204 authenticates, and then sends a CAS client to the set-top box 204.

Here, the CAS client may use information included in an Entitlement Management Message (EMM) and an Entitlement Control Message (ECM) to descramble the scrambled transport stream (eg, a control word). Perform the process of extracting.

In addition, the DCAS server 202 may transmit a Digital Rights Management (DRM) client and an Authorized Service Domain (ASD) client to the set-top box 204.

5 is a diagram illustrating a transport stream path in an open cable-based set-top box to which the DCAS is applied according to the present invention.

As shown in FIG. 5, after DCAS is applied to the open cable-based set-top box, the scrambled content output by the tuner 500 is directly input to the system on chip 504 without passing through the POD module 502.

As described above, the system-on-chip 504 is a chip that has a module for reproducing the transport stream transmitted from the headend 200, and decodes audio and video included in the signal output from the tuner 500. It may include a decoder 510.

In addition, the system-on-chip 504 includes a transmission processor 420 as in a typical open cable-based set-top box.

According to the present invention, the transport stream output from the tuner 500 is directly input to the transport processor 420, and the transport processor 420 is provided with a decryption key provided by the SM module 400 stored in software according to the present invention. For example, descrambling of the input transport stream is performed using a control word.

Meanwhile, the transmission processor 420 according to the present invention may further include a demux for extracting audio, video, and data from the signal output from the tuner 500.

As shown in FIG. 5, the controller 520 included in the set-top box 204 according to the present invention uses the downloaded DCAS host module and the SM module based on the scrambled content to the POD module 502. The descrambling is performed directly in the system on chip 504 without passing through.

In addition, the controller 520 controls the memory 522 to store the DCAS host image and the SM module.

6 is a flowchart illustrating a process of applying DCAS to an open cable-based set-top box according to the present invention.

FIG. 6 illustrates a process in which the open cable-based set-top box 204 communicates with the DCAS server 202 through a network to download an image and SM module for the DCAS host.

Referring to FIG. 6, after a connection is established between the open cable-based set-top box 204 and the DCAS server 202 (step 600), the DCAS server 202 transmits an image for the DCAS host to the set-top box 204. (Step 602).

In accordance with the download of the image for the DCAS host, the DCAS host module 410 is stored (step 604), and the modified platform code, porting layer and middleware are stored, and at the same time a DCAS interface for supporting communication with the DCAS host module is provided. Saved (step 606).

Thereafter, the DCAS server 202 transmits the SM module 400 to the set top box 204 (step 608).

Thereafter, the DCAS initialization process is performed according to the reboot of the set-top box 204 (step 610).

DCAS initialization is already defined in the DCAS standard, and authentication and transmission and reception of a predetermined message are performed between the DCAS server 202 and the SM boot loader 404 included in the SM module 400 during the initialization process.

After the DCAS initialization is completed, the DCAS server 202 transmits secret information for CAS client and user authentication to the set-top box 204 (step 612).

DCAS is applied to the open cable-based set-top box 204 through the above process.

In the above description, the SM module is downloaded to the set-top box 204 in the form of software, but according to another embodiment of the present invention, as shown in FIG. 7, a security processor 700 including the SM module is provided. The security processor 700 is configured to be inaccessible without authentication from the outside, and is connected to the system on chip 504 through the USB interface 702.

In general, since the open cable-based set-top box 204 has a USB interface 702, even if a USB dongle type security processor 700 having an SM module is provided, DCAS can be applied without changing the hardware.

Even when the smart card including the SM module is provided, the download of the image for the DCAS host and the download of the CAS client through the set-top box reboot and initialization are performed in the same manner as described above with reference to FIG. 6, and thus a detailed description thereof will be omitted. .

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Additions should be considered to be within the scope of the following claims.

1 is a view showing a transport stream path of a conventional open cable-based set-top box.

Figure 2 illustrates a DCAS application system according to an embodiment of the present invention.

3 illustrates a software architecture before and after applying DCAS according to the present invention.

4 illustrates the components of a DCAS.

5 is a diagram illustrating a transport stream path in an open cable-based set-top box to which the DCAS is applied according to the present invention.

6 is a flowchart illustrating a process of applying DCAS to an open cable-based set-top box according to the present invention.

7 is a block diagram of a set-top box to which DCAS is applied according to another embodiment of the present invention.

Claims (11)

In a method of applying a downloadable conditional access system (DCAS) to an open cable (OpenCable) based set-top box that can be equipped with an independent point of deployment (POD) module that interworks with a smart card according to the open cable standard, Downloading an image for a DCAS host including a DCAS host module; Downloading a Secure Micro (SM) module to send and receive messages to and from the DCAS host module; And Downloading a CAS (Conditional Access System) client that performs a function for descrambling the transport stream from the DCAS server, The transport stream is descrambled in a transport processor based on the DCAS host module and the SM module without passing through the POD module. The method of claim 1, The DCAS host image includes a modified platform code, middleware and porting layer for changing the set-top box to a DCAS host. The method of claim 2, At least one of the modified platform code, middleware, and the porting layer comprises a DCAS interface supporting communication between the DCAS host modules. The method of claim 1, The DCAS host module includes at least one of a limited reception network handler (CANH), a DCAS manager, and a SMD (SM Driver). The method of claim 1, The SM module may include at least one of a DCAS monitor and an SM bootloader. The method of claim 5, The CAS client download step, Including the authentication step between the DCAS server and the SM boot loader included in the SM module, If the authentication is completed, the DCAS server DCAS application method for transmitting the CAS client to the set-top box. delete The method of claim 1, The SM module is a DCAS application method is downloaded from the DCAS server. A tuner for receiving a scrambled transport stream; Independent POD (Point of Deployment) module to work with the smart card according to the open cable set-top box standard; A System on Chip including a decoder and a transmission processor; A memory configured to store an image for a DCAS host including a downloadable conditional access system (DCAS) host module and a secure micro (SM) module to establish a connection with the DCAS host module; And Controls the download of a Conditional Access System (CAS) client communicating with a DCAS server based on the stored SM module to perform a function for descrambling the transport stream, and the transport stream is based on the DCAS host module. A control unit for controlling to be descrambled in the transmission processor without passing through the POD module, And the SM module is downloaded from the DCAS server and stored in the memory. A tuner for receiving a scrambled transport stream; Independent POD (Point of Deployment) module to work with the smart card according to the open cable set-top box standard; A System on Chip including a decoder and a transmission processor; A memory for storing a DCAS host image and a DCAS host module including a downloadable conditional access system (DCAS) host module; A security processor of a universal serial bus (USB) dongle type, in which a secure micro (SM) module, which is connected to the DCAS host module, is stored; And Controls the download of a Conditional Access System (CAS) client communicating with a DCAS server based on the stored SM module to perform a function for descrambling a transport stream, wherein the transport stream is based on the DCAS host module. And a control unit for controlling the descrambling in the transmission processor without passing through the control unit. Downloadable Conditional Access System (DCAS) is installed in an OpenCable based set-top box that can be equipped with an independent Point of Deployment (POD) module that works with smart cards according to the OpenCable standard, and in a server connected via a network. As a method of application, Transmitting an image for a DCAS host including a DCAS host module to the set top box; Transmitting a SM (Secure Micro) module for transmitting and receiving a message with the DCAS host module to the set-top box; And And transmitting a CAS (Conditional Access System) client performing a function for descrambling a transport stream to the set-top box after authenticating the stored set-top box. And the set-top box descrambles the transport stream in the transport processor based on the DCAS host module and the SM module without passing through the point of deployment (POD) module.

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