KR20120090333A - System and method for allocating unique identification to cas client in exchangeable conditional access system - Google Patents

Abstract

PURPOSE: A unique identifier allocation system for a CAS(Conditional Access System) client in an exchangeable type restriction reception system is provided to store one CAS client image by allocating a unique identifier to the CAS client of each STB(Set Top box). CONSTITUTION: A SM(Security Module)(100) provides the SM certificate ID(Identification) of an SM certificate issued from an authentication agency. A head-end unit(300) allocates a unique identifier corresponding to the SM certificate ID. The head-end unit transmits the encryption of the unique identifier and matches the SM certificate ID with the unique identifier. A CAS client(200) transmits the encrypted unique identifier to the SM. The CAS client receives the decoded unique identifier from the security module.

Description

System and method for allocating unique identification to CAS client in eXchangeable Conditional Access System}

The present invention relates to a unique identifier assignment system and method for a CAS client in a switchable CA system, and more particularly, in a switchable CA system for assigning a unique identifier to a CAS client downloaded for each subscriber station of the XCAS system. A unique identifier assignment system and method for a CAS client.

Digital cable broadcasting can provide multimedia services including video and audio broadcasting signals as well as interactive services such as VOD (Video On Demand) and data broadcasting through HFC (Hybrid Fiber Cable) transmission network. It is a structure that can be combined with a telephone to accommodate various converged services.

Recently, cable broadcasting has been standardized and commercialized at the same time. For example, DOCSIS is applied to provide high-speed cable Internet service to subscribers, and in the case of digital cable broadcasting, OpenCalbe standards and OCAP (OpenCable Application Platform) are currently applied.

Based on the OpenCable standard and OCAP, conditional access system (CAS), which is a viewing authority control system of a user, which controls only subscribers who have obtained a viewing qualification through a legal procedure in the digital cable broadcasting, can watch a paid broadcasting program. ) Is provided.

In the conventional CA system, as illustrated in FIG. 1, a CAS client 10 that performs viewing authority control on pay broadcasting contents provided by a head-end for controlling viewing authority at a subscriber station side is illustrated in FIG. 1. ) Is composed of various types of non-replaceable hardware (including smart chips, smart cards, cable cards, and the like, and smart cards will be described below as an example).

Accordingly, the smart card 10 is mounted in the slot of the set-top box constituting the set-top box (STB) 20 to extract the encryption key from the key information provided from the headend to pay broadcast content Descrambling of the user is performed so that a user can watch a pay broadcast.

In this case, the headend may process the subscription or termination of the CA using a smartcard ID, which is a unique identifier issued when the smart card is manufactured, for subscriber management of the CA.

However, the smart card of the conventional CA system is an example of a CAS client composed of hardware, and a CAS client of various hardware such as a smart chip and a cable card having different specifications from the smart card is provided. There are also various configurations, there is a problem that does not support compatibility between the CAS client and the set-top box. That is, the subscriber can not replace the set-top box that supports the smart card corresponding to the smart card ID registered in the headend, and for this purpose, if a smart card or a cable card having a different specification is to be changed, the headend There is an inconvenience in that to register the unique identifier of the smart chip or cable card.

In addition, as shown in FIG. 1, for a device in which a set-top box is integrally formed with a TV, such as a Cable Ready TV 30, the CAS client 10 is built in hardware and is fixed in a conventional form. Of course, the integrated device is not compatible with the CAS client, but the integrated system is difficult to change the CA system. There is a problem that additional cost occurs because you need to purchase additional.

In order to overcome these disadvantages, the CAS client is configured as software, downloaded to the subscriber terminal, and supported for mobility and compatibility, so that the system introduced so that it can be easily exchanged is XCAS (eXchangeable CAS).

The interchangeable CA system securely downloads the CAS client from the headend to the SM (Secure Micro), which is a security module embedded in a subscriber terminal (Digital Cable STB), and the CAS downloaded to the security module. The client may provide the normal paid broadcast content only to a user who has a viewing authority by receiving the broadcast content scrambled with a predetermined encryption method through message exchange with the headend and performing descrambling, which is a decryption process.

Through this, the CAS system can be easily changed, and the cost of the subscriber station for physical device configuration can be greatly reduced.

However, the conventional CA system uses a unique identifier (for example, a smart card ID) of a CAS client configured as hardware as described in FIG. 1 issued at the time of manufacture to the physical device. While dealing with subscription or termination, the CAS client downloaded by XCAS is in the form of software, making it difficult to include identifiers within the CAS client.

For example, if you want to include a unique identifier within a CAS client, if you have a million subscribers, you store one million CAS client software in the head-end, and then download a CAS client for each subscriber terminal. Should be used.

In addition, a method of managing a unique number issued at the time of manufacture of the set-top box constituting the subscriber terminal by replacing the unique identifier at the headend has been sought, which secures all the unique numbers of the set-top box frequently replaced at the headend. There is a problem in that it is not suitable to replace a unique identifier.

In addition, in the XCAS standard, a method for securing an identifier of a CAS client is not defined as a standard, and a system for allocating a unique identifier for CAS client management is required.

An object of the present invention is to assign a unique identifier for each CAS client of an individual subscriber station operating based on the XCAS platform, so that subscriber management can be performed in the same manner as a conditional access system implemented with an existing physical device.

In addition, the present invention registers only one CAS client image that can be downloaded universally by all subscribing terminals in the CAS client repository included in the headend of XCAS, and has a unique identifier for each CAS client downloaded to each subscriber terminal at the headend. The purpose is to reduce the load on the headend and maximize the efficiency of identifier assignment for CAS clients.

In the switchable CA system according to the present invention for achieving the above object, a system for assigning a unique identifier for a CAS (Conditional Access System) client installed in a subscriber station is provided from a certification authority at the request of the CAS client. A security module (SM) providing an SM certificate ID of the issued SM certificate, and a unique identifier corresponding to the SM certificate ID is allocated according to a request of the CAS client, and encrypted with the public key of the SM certificate. The security module includes a headend for transmitting a client identifier and matching the SM certificate ID to store the unique identifier in a database, and an encrypted unique identifier received by transmitting the received SM certificate ID to the headend by requesting the security module. Receives and records the decrypted unique identifier from the security module It includes a CAS client.

In this case, when the CAS client downloads the CAS client from the headend or receives update information, the security module transmits a Timer Expired event to the downloaded or updated CAS client, and the CAS client receives the unique Timer Expired event. It may be characterized by requesting an SM certificate ID to the security module by checking whether the identifier is installed.

In addition, when receiving the update information, the security module sends a message about the update information to the CAS client to the CAS client, and the CAS client deletes the existing unique identifier based on the message, and then the Timer Expired The SM certificate ID may be transmitted to the headend in order to receive an event and receive a new unique identifier, and the headend may update the unique identifier previously stored in the database with the new unique identifier.

In the method for assigning a unique identifier to the CAS (Conditional Access System) client installed in the security module of the subscriber station in the switchable CA system according to the present invention for achieving the above object, A first step in which a security module mutually authenticates with the headend to download or update the CAS client, a second step in which the security module transmits a Timer Expired event to the CAS client where the download or update is completed, and the Timer Expired A third step in which the CAS client receiving the event checks whether a unique identifier is installed and requests the SM module the SM certificate ID of the SM certificate issued from the certification authority to receive the SM certificate ID from the security module; The client creates a communication session with the headend to A fourth step of requesting an assignment of a unique identifier by transmitting an ID, and the headend allocates a unique identifier corresponding to the SM certificate ID, stores the database in accordance with the SM certificate ID, and stores the unique identifier in the database. A fifth step of encrypting with a public key of an SM certificate and transmitting it to the CAS client; a sixth step of transmitting, by the CAS client, the encrypted data received from the headend to the security module to request decryption; and the security module A seventh step of decrypting the encrypted data to extract a unique identifier, transmitting the unique identifier to the CAS client, and an eighth step of recording the unique identifier by the CAS client.

In this case, when the security module receives the update information between the first step and the second step, transmitting a message about the update information to the CAS client to the CAS client, the CAS client based on the message The method may further include deleting an existing unique identifier. The fifth step may include updating, by the headend, a unique identifier previously stored in the database with a new unique identifier, and encrypting the new unique identifier with a public key of an SM certificate. It may be characterized in that the transmission to the client.

According to the present invention, a head-end of an exchangeable CA system assigns a unique identifier to a CAS client of each subscriber station (STB), so that a CAS client image that can be downloaded universally to all subscriber stations is obtained. Since only dogs can be registered, maintenance of the CAS client image is easy, and the unique identifier ensures convenience of subscriber management.

In addition, the present invention can enhance the security by encrypting the unique identifier of each terminal required by the CAS system to each subscriber terminal with an SM certificate installed in each subscriber terminal, and periodically updates the CAS client to update the unique identifier. It is effective to increase the security of subscriber information by updating.

1 is a view showing a unique identifier allocation scheme for a conventional subscriber station.
2 is a block diagram of a unique identifier assignment system for a CAS client in a switchable CA system according to the present invention;
3 is a flow chart of a method of assigning a unique identifier for a CAS client in a switchable CA.

The present invention is replaced with software in an exchangeable CA system, as in the existing CA system, subscriber management is performed using a unique identifier set in a CAS client configured with existing hardware that is attached to a subscriber terminal and performs viewing authority control. The present invention proposes a system that can easily perform subscriber management by assigning a unique identifier to each CAS client downloaded and installed for each subscriber station.

The present invention provides a security module (SM: Secure Micro) of a subscriber station from a trusted authority (TA) that is responsible for issuing and managing certificates used to provide a security function of an exchangeable CA system. A CAS ID, which is a unique identifier, may be allocated to a CAS client corresponding to an ID (hereinafter, SM certificate ID) of the SM certificate based on the SM certificate, thereby securely assigning a unique identifier for each CAS client of the authenticated subscriber station.

Prior to assigning the unique identifier, the security module can download the CAS client from the headend based on the SM certificate, and the CAS client installation and SM Boot process follows the standard of XCAS.

Referring to the downloading process of the CAS client, the security module can manage the SM certificate issued at the time of manufacture in a secure storage such as copy protection, and the information of the headend authenticated by the certification authority based on the SM certificate Can be obtained.

In addition, the headend receives the SM certificate ID transmitted from the security module by using the TA certificate and certificate revocation list information for authenticating the validity of the SM certificate from the certification authority to use the TA certificate and certificate revocation list information. The validity of the SM certificate corresponding to the SM certificate ID is verified to establish a session for communication with the security module with respect to the authenticated security module, and the security module may download the CAS client through the regular session.

Based on the above description, the unique identifier allocation process of the unique identifier allocation system for the CAS client in the switchable CA according to the present invention will be described in detail with reference to FIG. 2.

As shown in FIG. 2, the set-top box (STB) includes the security module 100 and the CAS client 200 downloaded to the security module 100, and the security module 100. And CAS client 200 may be configured to interoperate.

Therefore, when the first security module 100 is driven, the security module 100 receives service information (SI) information from the headend 300, and the headend 300 is a CAS installed in the security module 100. Send a command to check the integrity of the client 200.

Thereafter, the security module 100 performs mutual authentication as described above based on the headend 300 and the SM certificate, and receives the command to check or update the integrity of the currently installed CAS client 200. If there is no CAS client 200 currently installed, the headend 300 may request and download the CAS client 200.

When the above process is terminated, the security module 100 generates a Timer Expired event and transmits it to the CAS client 200, and the CAS client 200 confirms whether a CAS ID which is its unique identifier is installed. Can be.

In this case, when the CAS client 200 is updated, the security module 100 transmits update information on whether to update the CAS client 200, and the CAS client 200 is pre-stored based on the update information. You can delete the CAS ID.

Through this, the CAS client 200 updated by communicating with the headend 300 through the Timer Expired event after the update is completed may be assigned a new CAS ID, and the CAS ID is updated through such periodic update. Can be assigned by updating. That is, it is possible to prevent unauthorized users from copying CAS IDs through piracy and using them as subscribers.

If not installed, the CAS client 200 may request and receive an SM certificate ID from the security module 100, and generate the SM certificate ID received after creating a communication session with the headend 300. You can request a CAS ID by providing it.

Thereafter, the headend 300 may authenticate the validity of the SM certificate ID as the TA certificate, allocate the CAS ID corresponding to the authenticated SM certificate ID, and provide the CAS ID to the CAS client 200. . In this case, the headend 300 may store the assigned CAS ID with an authenticated SM certificate ID and store it in a database. If there is an existing CAS ID matching the SM certificate ID, the headend 300 updates the new CAS ID with the new CAS ID. Can be stored in a database.

In addition, the headend 300 encrypts the CAS ID and the additional information required for the CAS client to the CAS client 200 with a public key of the SM certificate to generate individualized data, and generates the individualized data. It may deliver to the CAS client 200.

Thereafter, the CAS client 200 may request decryption of the security module 100 by receiving the personalized data encrypted with the SM certificate, and the security module 100 decrypts the individualized data based on the SM certificate. The CAS ID in the decrypted data may be transmitted to the CAS client 200, and the CAS client 200 may record and store the CAS ID.

On the other hand, the identifier assignment method for the CAS client in the switchable CA system according to the present invention will be described in detail with reference to FIG.

As described above, according to the standard of the XCAS system, the initial driving time of the CAS client is a time for receiving a "Timer Expired" event from the security module, and the CAS client receiving the Timer Expired event is sent to the subscriber station (STB). Check that a dedicated unique identifier is installed. If it is not installed, it requests the SM certificate ID of the SM certificate issued from the certification authority to the security module to obtain a unique identifier (1).

Thereafter, the security module provides the SM certificate ID to the CAS client (2), and the CAS client creates a communication session to request the CAS ID to the headend (3). Accordingly, the CAS client requests a CAS ID from the headend through the created session (4), and the headend allocates a CAS ID according to the SM certificate ID (5).

In addition, the headend transmits the generated personalized data generated by encrypting the generated unique identifier and additional information required by the CAS client with the public key of the SM certificate to the CAS client (6), and the CAS client transmits the SM certificate. Receiving the encrypted personalized data with (7), and requests the decryption to the security module (8).

Thereafter, the CAS client receives the CAS ID decrypted by the SM (9) and records the CAS ID in the decrypted data (10).

100: security module 200: CAS client
300; Headend

Claims (5)

A unique identifier assignment system for a CAS (Conditional Access System) client installed in a subscriber station in a switchable CA system,
A security module (SM) for providing an SM certificate ID of an SM certificate issued from a certification authority at the request of the CAS client;
A headend for allocating a unique identifier corresponding to the SM certificate ID according to a request of the CAS client, encrypting it with the public key of the SM certificate, transmitting the encrypted identifier to the CAS client, and matching the SM certificate ID to store the unique identifier in a database; And
A CAS client that transmits the received SM certificate ID by requesting the security module to the headend and sends the encrypted unique identifier received to the security module to receive and record the decrypted unique identifier from the security module.
Unique identifier assignment system for the CAS client in the switchable CA system.
The method according to claim 1,
The security module transmits a Timer Expired event to the downloaded or updated CAS client when downloading the CAS client or receiving update information from the headend.
When the CAS client receives the Timer Expired event, the CAS client checks whether the unique identifier is installed and requests an SM certificate ID from the security module. .
The method according to claim 2,
When the security module receives the update information, the security module transmits a message about the update information to the CAS client, the CAS client,
The CAS client deletes the existing unique identifier based on the message, and then receives the Timer Expired event and transmits the SM certificate ID to the headend to be assigned a new unique identifier.
The headend is a unique identifier assignment system for a CAS client in a switchable CA system, characterized in that for updating the unique identifier previously stored in the database with the new unique identifier.
In the switchable CA system, the headend assigns a unique identifier to a CAS (Conditional Access System) client installed in a security module of a subscriber station.
A first step of the security module mutually authenticating with the headend to download or update the CAS client;
A second step of transmitting, by the security module, a Timer Expired event to the CAS client where the download or update is completed;
A third step of receiving the SM certificate ID from the security module by requesting the SM certificate ID of the SM certificate issued from the certification authority by the CAS client receiving the Timer Expired event to confirm whether the unique identifier is installed;
A fourth step of the CAS client creating a communication session with the headend and transmitting the SM certificate ID to request allocation of a unique identifier;
A fifth step in which the headend allocates a unique identifier corresponding to the SM certificate ID, stores the database in matching with the SM certificate ID, encrypts the unique identifier with a public key of the SM certificate, and transmits the unique identifier to the CAS client;
A sixth step of the CAS client requesting decryption by transmitting the encrypted data received from the headend to the security module;
A seventh step of the security module decrypting the encrypted data to extract a unique identifier and transmitting the unique identifier to the CAS client; And
An eighth step of recording, by the CAS client, a unique identifier
Unique identifier assignment method for a CAS client in a switchable CA system.
The method of claim 4,
Between the first and second steps
When the security module receives the update information, transmitting a message about the update information to the CAS client to the CAS client; And
The CAS client further includes deleting an existing unique identifier based on the message,
The fifth step is
The headend updates the unique identifier previously stored in the database with a new unique identifier, and encrypts the new unique identifier with the public key of the SM certificate and transmits the new unique identifier to the CAS client. How to assign a unique identifier for.

Images